Search found 125 matches

by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:44 pm
Forum: Phase Changes & Related Calculations
Topic: Heating Curve
Replies: 2
Views: 26

Re: Heating Curve

When solving phase change problems on our exam are we required to show a heating curve associated with it? It might not be required if they don't ask for it, however it is VERY helpful to draw one anyway so that you don't forget a calculation (as there are often so many steps associated with such p...
by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:42 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Strong/weak acids & bases
Replies: 14
Views: 97

Re: Strong/weak acids & bases

Are we going to have to know whether an acid or base is strong or weak just by its name or chemical formula? If so, how do we do know? For the final, you should memorize the strong acids and strong bases are there are not that many. Regarding weak acids and bases, given a scenario, and Ka and/or Kb...
by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:38 pm
Forum: Phase Changes & Related Calculations
Topic: delta G0 versus delta G
Replies: 15
Views: 85

Re: delta G0 versus delta G

Parker Smith wrote:What Is the difference between delta G0 and delta G, and why are they both in the delta G= delta GO+RTln(K equation?


Whenever anything has that tiny "o" (delta Go, Eo, So, Ho, etc) that just means standard conditions: 25C, 1bar/1atm, 1M.
It is pronounced "naught".
by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:36 pm
Forum: *Enzyme Kinetics
Topic: Poison a Catalyst
Replies: 3
Views: 18

Re: Poison a Catalyst

What exactly does it mean to poison a catalyst? Does this play a role when solving problems or answering any questions conceptually? In the textbook, I believe that they mentioned poisoning a catalyst just as an example of how if a poison is on the catalyst of a reaction, for example, an enzyme, an...
by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:32 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka Kb
Replies: 11
Views: 44

Re: Ka Kb

205150314 wrote:Just trying to reassure things before the midterm. When exactly can you tell that you would either need Ka or Kb?


If you have OH- being formed, you need Kb, if you have H+ or H30+, Ka.
Use Kw to convert between the two.
by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:30 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 7C.3
Replies: 2
Views: 21

Re: 7C.3

Write the overall reaction for the mechanism proposed below and identify any reaction intermediates. Step1 AC + B -> AB + C Step2 AC + AB -> A2B + C How do we approach these questions? For these types of questions, you would just place the reactants for both sides on the left of the arrow (in essen...
by Nicholas_Gladkov_2J
Tue Mar 10, 2020 9:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table
Replies: 5
Views: 24

Re: ICE table

When solving for concentrations with the ice table, in what situation can you assume x is too small and therefore can be excluded from the equation? EX: 0.2-x, in this situation would I just disregard x and just keep 0.2? When K is less than 10^-3, then you can disregard the change in concentration...
by Nicholas_Gladkov_2J
Sat Mar 07, 2020 11:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Purpose of Electrode
Replies: 9
Views: 92

Re: Purpose of Electrode

805312064 wrote:Sorry one more question! How would you write the electrode in a cell diagram?


For the cell diagrams, the electrodes go on the far left (electrode for the anode) and the far right (electrode for the cathode).
by Nicholas_Gladkov_2J
Sat Mar 07, 2020 11:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram Order
Replies: 8
Views: 65

Re: Cell Diagram Order

Does order matter when drawing cell diagrams? For example: Au(s)|Au 3+ (aq)|| or Au 3+ (aq)|Au(s)|| For drawing cell diagrams, the anode is on the left of the "||" and the cathode is on the right. The electrode are on the far left and the far right-- one for the anode and one for the cath...
by Nicholas_Gladkov_2J
Sat Mar 07, 2020 11:19 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Determining the cathode/anode
Replies: 9
Views: 69

Re: Determining the cathode/anode

How would you determine the cathode or anode of a cell by only knowing the E value of the half reactions (assuming the you don't know which electrode is being oxidized or which is being reduced)? To determine which is the anode, and which is the cathode, you look at the standard reaction potentials...
by Nicholas_Gladkov_2J
Sat Mar 07, 2020 11:16 pm
Forum: Balancing Redox Reactions
Topic: Half rxns
Replies: 27
Views: 156

Re: Half rxns

What differs when balancing acidic vs basic rxns? The difference between balancing acidic versus basic reactions is that they both are the exact same, except in the end of balancing, you will add the same amount of OH- on both sides of the balanced equation equal to the number of H+ in the reaction.
by Nicholas_Gladkov_2J
Sat Mar 07, 2020 11:13 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating ln Q
Replies: 20
Views: 162

Re: Calculating ln Q

Can someone explain what Q is and how to use it in the Nernst equation? Q is the equal to the concentration of products over reactants. In the concentration cells, if you find the two half reactions, you will find that Q is equal to the concentration of the anode, over the concentration of the anode.
by Nicholas_Gladkov_2J
Sat Mar 07, 2020 11:08 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: finding n in G=-nFE
Replies: 15
Views: 141

Re: finding n in G=-nFE

Hannah_1G wrote:How do you find n?


"n" is found by finding the two half reactions, and balancing them.
When balancing the half reactions, in order to balance the two half reaction charges, you will add electrons. The number of electrons in the reaction is the value of "n".
by Nicholas_Gladkov_2J
Sat Feb 29, 2020 9:38 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: diamond
Replies: 4
Views: 53

Re: diamond

can someone explain how a diamond is kinetically stable and thermodynamically unstable with respect to graphite? Think about the the activation energy. The process is favored (delta G is negative) for diamond to become graphite, but because of the large energy barrier (as it is kinetically trapped)...
by Nicholas_Gladkov_2J
Sat Feb 29, 2020 9:32 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: platinum
Replies: 5
Views: 28

Re: platinum

should we always use platinum for our cell diagram if we are not given a solid metal in the reaction? The purpose of platinum is to act as a conductor to transfer the electrons. It is used, when there is no conducting metal, so, YES, if we are not given a metal, but aqueous solutions, we will use p...
by Nicholas_Gladkov_2J
Sat Feb 29, 2020 9:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt bridges
Replies: 11
Views: 56

Re: Salt bridges

How does a salt bridge work and what is its effect on the battery? It is important to have the salt bridge, because it maintains the neutrality between the two solutions in the Galvanic cell. The anion is transferred from the cathode to the anode, while the electrons flow from the anode the the cat...
by Nicholas_Gladkov_2J
Sat Feb 29, 2020 9:24 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 16
Views: 397

Re: Activation Energy

AditiSax wrote:How can we define activation energy and represent it using energy profile diagrams?


Regarding the activation energy, this is why although the process if favored for diamond to become graphite, there is a large energy barrier (it is kinetically trapped).
by Nicholas_Gladkov_2J
Sat Feb 29, 2020 9:13 pm
Forum: Balancing Redox Reactions
Topic: When to add H+ or H20
Replies: 19
Views: 135

Re: When to add H+ or H20

When splitting up a redox reaction into its two separate half reactions, how do you know when you would add H20 or H+ to fix the amount of hydrogens one each side of an equation? When you need an O to balance the reaction, you add an H2O. When a H+ is needed, add an H+. If the reaction is basic, yo...
by Nicholas_Gladkov_2J
Sat Feb 29, 2020 9:09 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox Reactions
Replies: 3
Views: 26

Re: Balancing Redox Reactions

What are the steps to balance a redox reaction in acidic or basic solution? For balancing redox reactions, you first will first find the oxidation half reaction (loss of e-) and the reduction half reaction (gain of e-). For each you will then balance: When an oxygen is needed, you will add an H20. ...
by Nicholas_Gladkov_2J
Sat Feb 22, 2020 11:41 pm
Forum: Balancing Redox Reactions
Topic: Reducing agent/oxidizing agent
Replies: 5
Views: 39

Re: Reducing agent/oxidizing agent

What is the method for determining whether a reactant is a reducing or an oxidizing agent? I am having trouble determining the oxidation number. For the hw problems I determined whether the reactant is an oxidizing or reducing agent by writing the half reactions and seeing which side the electrons ...
by Nicholas_Gladkov_2J
Sat Feb 22, 2020 11:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: relevance of salt bridge
Replies: 9
Views: 29

Re: relevance of salt bridge

Ryan Yoon 1L wrote:Why do we put a porous/salt bridge in beakers that have the cathode and anode?


Salt bridges are used in order for the two solution of the Galvanic cell to remain neutral. This is done by allowing ions, such as Cl-, to transfer from the side of the anode, to the side of the cathode.
by Nicholas_Gladkov_2J
Sat Feb 22, 2020 11:29 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Using Pt
Replies: 7
Views: 41

Re: Using Pt

When is it necessary to use Pt(s) in the skeletal equation of a redox reaction? In the example that Dr. Lavelle gave in class: 2Fe3+(aq) + Cu(s) -> Cu2+(aq) + 2Fe2+ although platinum is part of the redox reaction, platinum is an inert conductor that is transferring e-, as there is no conducting sol...
by Nicholas_Gladkov_2J
Sat Feb 22, 2020 11:19 pm
Forum: Balancing Redox Reactions
Topic: Calculating the reaction Gibbs free energy
Replies: 7
Views: 42

Re: Calculating the reaction Gibbs free energy

vpena_1I wrote:In ∆G*=-nFE*, is n the number of moles of the species that is being reduced?


In this equation, "n" is referring to the number of moles of e- that are being transferred.
For the half-reactions remember to balance your reaction!
by Nicholas_Gladkov_2J
Sat Feb 22, 2020 11:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: single line in cell diagram
Replies: 3
Views: 15

Re: single line in cell diagram

If I'm looking at a typical picture of reaction in a galvanic cell, what would be the corresponding part to the single line(s) in a cell diagram? In Dr. Lavelle's slides, he wrote that the single line represents interface between phases in contact with each other (including porous disk/wall). So, i...
by Nicholas_Gladkov_2J
Sat Feb 22, 2020 11:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 10
Views: 57

Re: Salt Bridge

I know a salt bridge is there to keep both solutions neutral, but what exactly is going on inside the salt bridge that allows it to contribute to the galvanic cell? In order for the two solutions of the Galvanic cell to stay neutral (because there is an exchange of e-), the ions (for example Cl-) m...
by Nicholas_Gladkov_2J
Sat Feb 15, 2020 10:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium
Replies: 15
Views: 91

Re: Equilibrium

Why is delta G naught 0 at equilibrium? When delta G is negative, the reaction is spontaneous. When delta G is positive it is not spontaneous, but you could think of the reverse reaction to be favored. So, when delta G is negative, there is not a preference to proceed to products, nor is there a fa...
by Nicholas_Gladkov_2J
Sat Feb 15, 2020 10:09 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: adiabatic
Replies: 19
Views: 114

Re: adiabatic

Kaylee Clarke 1G wrote:what is an adiabatic process?


What is meant by an adiabatic process is that there is no change in heat, q.
This is not to be confused with isothermal where the change in temperature is 0.
by Nicholas_Gladkov_2J
Sat Feb 15, 2020 10:07 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: S vs Stotal
Replies: 7
Views: 74

Re: S vs Stotal

vanessas0123 wrote:What is the difference between delta S and delta S total?


What is meant by delta S, it is the entropy of the system.
Delta S total is the entropy of both the system and the surroundings.
by Nicholas_Gladkov_2J
Sat Feb 15, 2020 10:05 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs free energy
Replies: 5
Views: 35

Re: Gibbs free energy

Why does Gibbs free energy depend on the equilibrium constant and pressure? Also, is Gibbs free energy a state function? Yes! Gibbs free energy, G, is a state function. It it determined by its current state. This allows us to calculate the chnage based upon the final and inital values-- this is sim...
by Nicholas_Gladkov_2J
Sat Feb 15, 2020 9:17 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: THe first law definition
Replies: 5
Views: 56

Re: THe first law definition

what is the simplest way to think about the first law of thermodynamics? The first law of thermodynamics states that the internal energy is equal to the work into the system minus the heat of the system. So, if work is performed on the system, then U increases. If heat is added to the system, then ...
by Nicholas_Gladkov_2J
Sat Feb 15, 2020 9:08 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal
Replies: 9
Views: 67

Re: Isothermal

Does isothermal mean the same thing as reversible? No, although isothermal reactions could very well be reversible. Isothermal means that a reaction has no change in temperature, while reversible means that there are slight changes made in pressure, and the temperature doesn't change. So, I guess t...
by Nicholas_Gladkov_2J
Sat Feb 08, 2020 12:36 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Closed Systems
Replies: 13
Views: 58

Re: Closed Systems

What were the ways that a closed system can be changed? Was it only by changing the temperature and/or volume? A closed system can have changes that do not affect the amount of "stuff" that is within it's container. The volume and pressure and have an effect on the system, so long as the ...
by Nicholas_Gladkov_2J
Sat Feb 08, 2020 12:34 pm
Forum: Calculating Work of Expansion
Topic: Isothermal
Replies: 17
Views: 98

Re: Isothermal

If the expansion of the gas is isothermal, then this means the temperature remains constant and delta U = 0 Could you explain why delta U would equal 0? I'm a little confused about the connection between temperature and delta U. We know that delta U= q + w and delta U=(3/2)nR(deltaT) if delta T=0 t...
by Nicholas_Gladkov_2J
Sat Feb 08, 2020 12:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Addition of a solid product/reactant
Replies: 3
Views: 23

Re: Addition of a solid product/reactant

vibha gurunathan 1h wrote:If you add a solid product/reactant, does the reaction shift? (b/c it isn't in the K expression)


No! You only consider gases and aqueous solutions! There is no molarity of liquid water, and there's no molarity of a solid.
So when solving for K, you leave out the solids and liquids.
by Nicholas_Gladkov_2J
Sat Feb 08, 2020 12:10 pm
Forum: Phase Changes & Related Calculations
Topic: General Phase Change Calculations
Replies: 6
Views: 38

Re: General Phase Change Calculations

For phase change questions, when do you know to start off with q=mcdeltaT to find the heat and when to use the Hvap etc.? For example, why do you use q=mcdeltaT first in question 4.1 where as in 4C.13 you use H=6.01 kJ/mol first? You start off with q=cmdeltaT when the current state of the substance...
by Nicholas_Gladkov_2J
Sat Feb 08, 2020 12:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard enthalpies of formation
Replies: 5
Views: 24

Re: Standard enthalpies of formation

When finding the total enthalpy of the reaction and you can use the method of standard enthalpies of formation, do you multiply each enthalpy of formation value by the stoichiometric coefficient? Yes! To find the standard enthalpy of the reaction, you multiply the standard enthalpy of formation of ...
by Nicholas_Gladkov_2J
Sat Feb 08, 2020 11:47 am
Forum: Phase Changes & Related Calculations
Topic: Enthalpy of a combustion reaction?
Replies: 7
Views: 35

Re: Enthalpy of a combustion reaction?

Is Delta H positive or negative for a combustion reaction? If delta H is positive, this means that heat was absorbed in the chemical reaction (endothermic), and thus the surroundings loose heat, or become cold. The opposite is true for negative delta H. This means that heat was released in the chem...
by Nicholas_Gladkov_2J
Sat Feb 01, 2020 7:01 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated systems
Replies: 4
Views: 37

Re: Isolated systems

When differentiating between a closed system and an isolated system, do we assume that the insulation of a calorimeter is close to 100% effective, or should we analyze if the system's insulator will leak heat into the surroundings? Most likely, when the question states that the system is isolated, ...
by Nicholas_Gladkov_2J
Sat Feb 01, 2020 6:56 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Pressure in an open beaker
Replies: 12
Views: 59

Re: Pressure in an open beaker

Maya Gollamudi 1G wrote:In an open beaker system, how do we know that the system is at constant pressure?



The pressure in an open beaker is constant.

The surrounding system is so large that your reaction will have virtually no influence on the surrounding system's pressure; as a result, your pressure is constant.
by Nicholas_Gladkov_2J
Sat Feb 01, 2020 6:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of Rxn
Replies: 9
Views: 47

Re: Enthalpy of Rxn

If the enthalpy of a reaction is 300kJ/mol, and we have 0.05mol of th substance, do we multiply or divide by the moles of the substance to find the enthalpy of the reaction? Usually if I'm stuck on deciding whether not to multiply or divide I look at the units. Think about what units you want in th...
by Nicholas_Gladkov_2J
Sat Feb 01, 2020 6:48 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work
Replies: 6
Views: 52

Re: Work

Rachel Yu 1G wrote:When is work positive or negative and why?


If something is doing work then w is negative, if something has having work done on it w is positive.
by Nicholas_Gladkov_2J
Sat Feb 01, 2020 6:45 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: isolated system
Replies: 13
Views: 51

Re: isolated system

can someone give examples of an isolated system? Think of an isolated system as a very good thermos. You wouldn't want any contents of your thermos to come out and you wouldn't want your contents to become cold. So with an isolated system, no heat is exchanged with the surroundings, and no matter i...
by Nicholas_Gladkov_2J
Sat Feb 01, 2020 6:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed vs isolated systems
Replies: 24
Views: 97

Re: Closed vs isolated systems

Can somebody explain the difference between closed and isolated systems? I don't really understand the difference based off of the textbook definitions. I think that one of the best examples of a closed system is a thermometer. With a closed system, there is an exchange of heat, so with the thermom...
by Nicholas_Gladkov_2J
Sat Jan 25, 2020 2:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Percent Ionization
Replies: 12
Views: 56

Re: Percent Ionization

Deja Nora wrote:How do we calculate percent ionization?


Percent ionization is equal the final concentration of the ionized acid divided by the initial concentration of the acid multiplied by 100%.
by Nicholas_Gladkov_2J
Sat Jan 25, 2020 2:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q<K
Replies: 11
Views: 59

Re: Q<K

Why is it that if Q<K, the forward reaction is favored if [R]>[P]? As Q and K are both the concentration of products over reactants, if Q is less than K, then in order for Q to be equal to K, Q has to get bigger. In order for Q to get bigger, the concentration of products have to be larger. Therefo...
by Nicholas_Gladkov_2J
Sat Jan 25, 2020 2:50 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Melting and freezing
Replies: 7
Views: 39

Re: Melting and freezing

If enthalpy of fusion is an endothermic reaction, would freezing be an exothermic reaction? Yes, freezing would be an exothermic reaction. If you think about it, in order for something to be melted, energy needs to be put into it so energy needs to be taken out of something to be frozen. A lot of t...
by Nicholas_Gladkov_2J
Sat Jan 25, 2020 2:47 pm
Forum: Phase Changes & Related Calculations
Topic: Bond Enthalpies
Replies: 5
Views: 31

Re: Bond Enthalpies

Can someone explain Lavelle's second method to measure enthalpy changes by using bond enthalpy. I got a little lost. Thanks! With the second method, it is best to draw out the Lewis structure to fully understand what is going on. So, for the second method, you are looking at how the two molecules b...
by Nicholas_Gladkov_2J
Thu Jan 23, 2020 12:32 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H20 in the ICE table
Replies: 26
Views: 137

Re: H20 in the ICE table

Alexis Robles 2k wrote:is H20 the only thing we leave out when doing an ICE table?


In ICE tables, you leave out liquids and solids, so if that water is in liquid form, you leave it out. If that water is in gaseous form, you do have to include it in the ICE table.
by Nicholas_Gladkov_2J
Thu Jan 23, 2020 12:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le chatelier and Temperature
Replies: 9
Views: 64

Re: Le chatelier and Temperature

I know this depends on the delta H, but what happens if the temperature is changed? For example: delta H is positive and temperature is increased, what would happen? Delta H helps you determine if the reaction is exothermic or endothermic. If the reaction is endothermic, then heat is needed and is ...
by Nicholas_Gladkov_2J
Thu Jan 16, 2020 5:08 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Product Yield
Replies: 6
Views: 31

Re: Product Yield

Zoya Mulji 1K wrote:How would you change the yield of a product without adding more reactants?


To acquire more products without adding more reactants, you would want to remove the products, such that the forward reaction is favored and more products will be made.
by Nicholas_Gladkov_2J
Thu Jan 16, 2020 5:04 pm
Forum: Ideal Gases
Topic: PV=nRT equation manipulation
Replies: 13
Views: 141

Re: PV=nRT equation manipulation

What was the purpose of changing the equation to equal P or the concentration? Will this be further manipulated when we deal with equilibrium? The purpose of manipulating PV=nRT is purely to acquire the information that is asked for in the problem, as well as to understand certain concepts. Solving...
by Nicholas_Gladkov_2J
Thu Jan 16, 2020 4:59 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endo/exothermic
Replies: 3
Views: 28

Re: Endo/exothermic

In a reaction where X2 -> 2X is it considered endothermic or exothermic and why? (X stands for any element) If bonds are broken, it requires energy, thus in the reaction that you gave, it would be endothermic (requires energy to proceed). If bonds are created, it releases energy, thus in the revers...
by Nicholas_Gladkov_2J
Thu Jan 16, 2020 4:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximation
Replies: 8
Views: 45

Re: Approximation

Can someone explain how and when we use approximation for ICE tables? Are there other situations you can use them as well? Is this only for acids and bases? If the K value is less than 10^-3, then for the creation of the equation that is equivalent to the equilibrium constant, it is acceptable to r...
by Nicholas_Gladkov_2J
Thu Jan 16, 2020 4:44 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: How to make ICE box
Replies: 17
Views: 133

Re: How to make ICE box

I understand the initial and equilibrium rows in the ICE box but how do you figure out the change row? That is, how do you figure out what the change in concentration will be? What is in the change row is determined by the stoichiometric coefficients of the balanced chemical equation. If in the ini...
by Nicholas_Gladkov_2J
Thu Jan 16, 2020 4:39 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 4
Views: 26

Re: Q and K

What does it mean in terms of which way the reaction will proceed if Q is less than K? Greater than K? Remember that K and Q are solved for by the concentration of the products over the concentration of the reactants. If Q is greater than K, then that means that the concentration of products is hig...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 13
Views: 107

Re: Q vs K

This may be an obvious question, but what is the difference between Q (reaction quotient) and K (equilibrium constant)? k is a constant that is temperature dependent (one per temperature) that is solved when the reaction reached equilibrium. Q is when the reaction has not reached equilibrium, but i...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Catalysts
Replies: 7
Views: 41

Re: Catalysts

Can someone define a catalyst with examples and explain how it affects a reaction? A catalyst merely speeds up a reaction. It does not "make more product" or "make more reactant," however, as it speeds up a reaction, it may result in the reaction to reach equilibrium faster than...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:44 pm
Forum: Ideal Gases
Topic: K vs Q [ENDORSED]
Replies: 7
Views: 55

Re: K vs Q [ENDORSED]

I have a question about when to use K and Q. Also, what's the main difference between the two. Thank you. :) k is the equilibrium constant that is temperature dependent (the same number for every temperature); it does not change unless temperature changes (as long as the reaction is at equilibrium)...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between K and Q
Replies: 6
Views: 33

Re: Difference between K and Q

What is the difference between the equilibrium constant K and the reaction quotient Q? Does K remain constant, while Q is subject to change? k is the EQUILIBRIUM CONSTANT. Q is just like k (in the sense that you solve for it exactly like k), however it is for when an the concentrations are NOT IN E...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to do ice tables [ENDORSED]
Replies: 4
Views: 29

Re: When to do ice tables [ENDORSED]

How do we know when to use an ICE table to find the composition of the mixture, or when we have to use only the K=[products]/[reactants] equation? Is it dependent on whether initial concentrations or equilibrium concentrations are given? Yes! What you decide to do in order to solve what is asked is...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:31 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding inert gas [ENDORSED]
Replies: 9
Views: 54

Re: Adding inert gas [ENDORSED]

How come adding inert gas to a reaction vessel would result in no change to the concentrations of the reactants and products? If nothing changes, what's the effect or purpose of adding the gas then (besides increasing pressure)? Adding an inert gas does not change concentration of the reactants and...
by Nicholas_Gladkov_2J
Sat Jan 11, 2020 9:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE box
Replies: 9
Views: 48

Re: ICE box

When calculating the change in molar concentration with the quadratic equation, and the results are one positive number and one negative number, would there ever be a circumstance where the negative number is also an acceptable answer? It's all about context. If the value of x is negative, however ...
by Nicholas_Gladkov_2J
Sat Dec 07, 2019 12:22 am
Forum: Lewis Structures
Topic: Ozone lewis structure
Replies: 3
Views: 54

Re: Ozone lewis structure

Why is ozone's lewis structure drawn as one double bond and one single bond? Why is it not two double bonds with the formal charges on the oxygens all equal 0? If you draw ozone with two double bonds, then there isn't the 18 electrons that is needed for the lewis stucture of ozone (3x6 = 18), there...
by Nicholas_Gladkov_2J
Sat Dec 07, 2019 12:15 am
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Rod vs spherical shaped molecules
Replies: 8
Views: 91

Re: Rod vs spherical shaped molecules

Can someone explain the key differences between rod shaped and spherical shaped molecules? The main thing to remember with the rod shaped molecules is that they are closer to one another and thus the strength of the LDF is greater. With the spherical shaped molecules, they are father apart form eac...
by Nicholas_Gladkov_2J
Sat Dec 07, 2019 12:07 am
Forum: Administrative Questions and Class Announcements
Topic: THE SONG DJ LL PLAYS AT THE BEGINNING OF CLASS [ENDORSED]
Replies: 7
Views: 579

Re: THE SONG DJ LL PLAYS AT THE BEGINNING OF CLASS [ENDORSED]

Elizabeth Johnson 1I wrote:it's Numb by Portishead
I found it out and thought it should be known by the general public that's all


Thank you Elizabeth for answering a question I've had for 10 weeks!
by Nicholas_Gladkov_2J
Sat Dec 07, 2019 12:04 am
Forum: Polyprotic Acids & Bases
Topic: Definition of Polyprotic
Replies: 5
Views: 67

Re: Definition of Polyprotic

NicoJones_1B wrote:What are the definitions of polyprotic acids and bases?


Polyprotic refers to many protons.
Bases accept protons, acids donate protons, so polyprotic acids donate many protons, while polyprotic bases accept more than one proton.
by Nicholas_Gladkov_2J
Sat Dec 07, 2019 12:01 am
Forum: Dipole Moments
Topic: London Dispersion Forces
Replies: 4
Views: 54

Re: London Dispersion Forces

NicoJones_1B wrote:Do all molecules have london dispersion forces?


Yes, all molecules have LDF because think of the electrons as constantly moving, so there are dipoles that are induced attracted to other induced dipoles. That's why LDF can also be referred to as induced dipole induced dipole.
by Nicholas_Gladkov_2J
Fri Dec 06, 2019 11:57 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: is h-bonding different than dipole-dipole
Replies: 3
Views: 50

Re: is h-bonding different than dipole-dipole

Is hydrogen bonding a form of dipole-dipole force, and if not, do we have to list both in a molecule like NH3? Hydrogen bonding is a type of dipole dipole IMF. Dipole dipole is when there is a pull of the electrons towards a certain atom/direction, and H-bonding is when that pull is with a hydrogen...
by Nicholas_Gladkov_2J
Fri Dec 06, 2019 11:53 pm
Forum: Identifying Acidic & Basic Salts
Topic: Basic Salts
Replies: 2
Views: 37

Re: Basic Salts

How and when does a salt containing a base change the pH of a solution? Matthew spoke in the review session that salts whose cations come from weak bases will act as an acid and will lower the pH, and if the anions come from weak acids they will act as bases and raise the pH. There is more practice...
by Nicholas_Gladkov_2J
Sat Nov 30, 2019 5:13 pm
Forum: Air Pollution & Acid Rain
Topic: Clean Coal vs Dirty Coal?
Replies: 16
Views: 144

Re: Clean Coal vs Dirty Coal?

can someone explain the difference between clean coal and dirty coal? I remember it being explained in the lecture in terms of Carbon of Sulfur dominant, but I don't remember which was clean and which was dirty. The difference between clean coal and dirty coal is the amount of sulfur content in the...
by Nicholas_Gladkov_2J
Sat Nov 30, 2019 5:08 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Shortcut for Formal Charge
Replies: 14
Views: 157

Re: Shortcut for Formal Charge

Does anyone know any short method or trends that make it easier to know/calculate the formal charge of an atom? Like creating a double bond would help the formal charge to be more towards zero etc? For formal change, a fast way to check (although you should do the calculation (FC = valence - (#bond...
by Nicholas_Gladkov_2J
Sat Nov 30, 2019 5:01 pm
Forum: Bond Lengths & Energies
Topic: Strongest Bonds
Replies: 11
Views: 134

Re: Strongest Bonds

In our notes it says bonds between two ions have -250kJ of energy and are most favorable. Is the next most favorable type of bond, a Hydrogen bond? I think the order of the strength of the IMFs according to the textbook (strongest to weakest, by Ep/(kJmol^-1) is: Ion-ion, hydrogen-bonds, ion-dipole...
by Nicholas_Gladkov_2J
Sat Nov 30, 2019 4:57 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids & Bases vs Bronsted Acids & Bases
Replies: 2
Views: 22

Re: Lewis Acids & Bases vs Bronsted Acids & Bases

Hi! What is the difference between the "types" or "definitions" of the acids and bases? I feel like the definitions are predicated on the same idea of being an electron donor or receiver so I am a bit confused. Thanks! There are two definitions of acids and bases. For the Bronst...
by Nicholas_Gladkov_2J
Sat Nov 30, 2019 12:02 am
Forum: Lewis Acids & Bases
Topic: Proton acceptor and proton donor?
Replies: 33
Views: 187

Re: Proton acceptor and proton donor?

Kimberly Bauer 4E wrote:Which is a proton acceptor and which is the proton donor? I always forget it lol


A Bronsted acid donates a proton.
A Bronsted base accepts a proton.

This is different than

A Lewis acid accepts an e- pair.
A Lewis Base donates an e- pair.
by Nicholas_Gladkov_2J
Fri Nov 29, 2019 11:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Metal Oxidation Number
Replies: 3
Views: 24

Re: Metal Oxidation Number

Is there a quick formula or trick that can give me the oxidation state of a metal in a a coordination compound? I think that the best way to figure out the oxidation number of a metal is just to look at the given equation and subtract the charges of the ligands from the total net charge until you o...
by Nicholas_Gladkov_2J
Sat Nov 23, 2019 11:56 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Boiling Points
Replies: 9
Views: 71

Re: Boiling Points

What intermolecular forces cause higher boiling points? Lower boiling points? And what are some examples? Something will have a higher boiling point when the IMFs are stronger, or there are more of them that makes them stronger. If something has two hydrogen bonds it will have a higher boiling poin...
by Nicholas_Gladkov_2J
Sat Nov 23, 2019 11:49 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE formula
Replies: 32
Views: 1968

Re: AXE formula

is it possible to determine the shape of a molecule if you're only given the AXE formula, if so how do you do it? The formula tells you how many lone pairs as well as how many attached atoms there are to the central atom. The subscript after X is how many atoms attached to the central atom. In AX2E...
by Nicholas_Gladkov_2J
Sat Nov 23, 2019 11:42 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Best Approach to Find IMFs
Replies: 11
Views: 105

Re: Best Approach to Find IMFs

What are your best methods for finding intermolecular forces of a molecule? Do we start out with drawing the Lewis structure? yes, drawing the Lewis structure is the best first step, because it will help you best visualize, as much as possible, what is happening regarding which atoms are attached t...
by Nicholas_Gladkov_2J
Sat Nov 23, 2019 11:30 pm
Forum: Naming
Topic: Prefixes
Replies: 4
Views: 36

Re: Prefixes

Tracey Tran 3I wrote:When do we use the prefixes, bis, tris, tetrakis, pentakis?


As Tracy Tran mentioned it's when the ligand already has the prefixes di-, tri-, etc. In class, I think I remember Dr. Lavelle mentioning how it's just so you don't say "di- di-" or other prefixes multiple times.
by Nicholas_Gladkov_2J
Sat Nov 23, 2019 11:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shaped v. Trigonal pyramid
Replies: 9
Views: 77

Re: T-shaped v. Trigonal pyramid

Just for clarification, T-shaped is 3 atoms with 2 lone pair and trigonal pyramidal is 3 atoms with 1 lone pair, correct? Thanks! T-shaped electron shape is trigonal bipyramidal, so think of that shape, but then replace two atoms with electron lone pairs, to get the molecular shape, so yes, you get...
by Nicholas_Gladkov_2J
Sat Nov 23, 2019 11:20 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 7
Views: 39

Re: Sigma and Pi Bonds

To my understanding, Sigma bonds are between single bonds and are able to rotate and Pi bonds are the bonds after the first bond of a sigma bond and cannot rotate. Do we need to know anything else for these types of bonds? Regarding sigma and pi bonds I think that the most important things to know ...
by Nicholas_Gladkov_2J
Sat Nov 16, 2019 9:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent and Angular?
Replies: 6
Views: 49

Re: Bent and Angular?

Ghadir Seder 4F wrote:When referring to structures, are bent and angular the same thing?


I also was confused when I saw that in the book it was referred to as angular, and in class it was bent, but they are the exact same thing! 2 attached atoms and zero lone pairs.
by Nicholas_Gladkov_2J
Sat Nov 16, 2019 9:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. Nonpolar
Replies: 12
Views: 100

Re: Polar vs. Nonpolar

Can someone explain how to determine if a molecule is polar or non polar by looking at its molecular geometry/shape? By looking at the shape of the molecule, yes, most likely you can determine the polarity of that molecule. If the shape is linear, tetrahedral, and octahedral most likely the shape w...
by Nicholas_Gladkov_2J
Sat Nov 16, 2019 9:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: How to treat Radicals
Replies: 5
Views: 62

Re: How to treat Radicals

If a radical is treated as 1 region of electron density, similar to a lone pair, does it also take up a larger region and create greater electron repulsion than a bonding-bonding pair? In class, Dr. Lavelle said that radicals are one region of electron density. They do have electron repulsion, but ...
by Nicholas_Gladkov_2J
Sat Nov 16, 2019 9:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 8
Views: 58

Re: Bond Angles

How do you calculate the bond angles for molecules? Bond angle are something that you just have to memorize (109.5 for tetrahedral, etc.). However, many bond angles for molecules are quite intuitive, for example, for linear it is 180. It can be confusing when an angle of less than an angles, but th...
by Nicholas_Gladkov_2J
Sat Nov 16, 2019 9:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: What is VSPER
Replies: 14
Views: 178

Re: What is VSPER

what does VSPER stand for and do we need to memorize it? VSEPR is an acronym for "valence-shell-electron-pair-repulsion" model. It explains experimentally the observed shape of molecules. Yes, we need to know it 100% as it encompasses all the various shapes that we will have to determine ...
by Nicholas_Gladkov_2J
Sat Nov 16, 2019 9:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar or non polar?
Replies: 7
Views: 50

Re: polar or non polar?

how can you tell if a molecule is nonpolar or polar based on its lewis structure? or can you only tell from the difference in electronegativity? You would use both the lewis structure and the electronegativity to tell if the molecule is polar or non-polar. For example, in class when Dr. Lavelle sho...
by Nicholas_Gladkov_2J
Sat Nov 09, 2019 6:04 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen bonding
Replies: 8
Views: 46

Re: Hydrogen bonding

NicoJones_1B wrote:Why will hydrogen only form bonds with highly electronegative atoms?


In lecture, Dr. Lavelle, said that hydrogen bonds form only when a hydrogen atom is covalently bonded to N, O, F atoms and is close to another electronegative atom (I'm assuming N, O, F) that has a lone pair nearby.
by Nicholas_Gladkov_2J
Sat Nov 09, 2019 5:59 pm
Forum: Lewis Structures
Topic: When to draw Resonance Structures
Replies: 14
Views: 104

Re: When to draw Resonance Structures

For the midterm, should we always draw the resonance structures or will we be okay with drawing the most stable structure? I guess more clearly I am wondering if Dr. Lavelle will specify "draw the Lewis Structure and its resonance forms" or should we still draw the resonance structures if...
by Nicholas_Gladkov_2J
Sat Nov 09, 2019 5:54 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 18
Views: 117

Re: Drawing Lewis Structures

When drawing regular lewis structures do you always have to draw them where their formal charges are zero? The lower the formal charge, the more stable the structure. In theory, yes the formal charges for each atom doesn't have to be zero, but the closer to zero the better, because of this stability.
by Nicholas_Gladkov_2J
Sat Nov 09, 2019 5:47 pm
Forum: Dipole Moments
Topic: London forces
Replies: 9
Views: 72

Re: London forces

AlyssaYeh_1C wrote:Why is the london interaction considered "universal"?


The reason why the force is considered universal, is because it is always present and attractive for all molecules because all have electrons. The fluctuating electrons distribution causes the fluctuating dipoles.
by Nicholas_Gladkov_2J
Sat Nov 09, 2019 5:40 pm
Forum: Bond Lengths & Energies
Topic: Bonds
Replies: 6
Views: 57

Re: Bonds

Aedra Li 3H wrote:What is the difference between pi bonds and sigma bonds?


Single Bonds: All single bonds are sigma bonds.
Double Bonds: In double bonds on is a sigma bonds, the other is a pi bond.
Triple bonds: One is a pi bond, the other two are sigma bonds.
by Nicholas_Gladkov_2J
Sat Nov 09, 2019 5:37 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarisability vs Polarizing Power
Replies: 15
Views: 159

Re: Polarisability vs Polarizing Power

What is the difference between Polarisability and Polarizing Power? Polarizabilty are anions that are large. You can think of it as the ability to be polarized, so the larger it is the more ability to be affected but the cation. Polarizing power is the small cation that causes the atom that has a l...
by Nicholas_Gladkov_2J
Sat Nov 02, 2019 3:53 pm
Forum: DeBroglie Equation
Topic: Dino Nuggets 13.2
Replies: 2
Views: 74

Re: Dino Nuggets 13.2

(b) Matt walks in, hoping to absorb some of the potassium ions in the air to alleviate his cramps. He thinks to himself, “I wonder what the frequency of the potassium ion is?” and divides the speed of light by the wavelength to obtain a frequency of 2.671x10^16 Hz for each potassium ion. Is he corr...
by Nicholas_Gladkov_2J
Sat Nov 02, 2019 3:48 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 6
Views: 57

Re: Work Function

What exactly is the definition of work function? If it's the energy needed to remove a single electron from solid metal, why is the unit sometimes J per mole? The work function is energy to remove e-. Usually you want the units to be joules per electron (the amount of joules to remove one e-), So, ...
by Nicholas_Gladkov_2J
Sat Nov 02, 2019 3:41 pm
Forum: DeBroglie Equation
Topic: Converting mass to kilograms for de broglie
Replies: 7
Views: 38

Re: Converting mass to kilograms for de broglie

If a problem wants you to find the wavelength of an ion or an atom given the speed its traveling and no other information, how do you get the mass of the singular atom? If it was potassium for example, would you use the molar mass of potassium, change it to kilograms, and then divide by avogadros n...
by Nicholas_Gladkov_2J
Sat Nov 02, 2019 3:34 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What are the octet exceptions?
Replies: 11
Views: 83

Re: What are the octet exceptions?

n = 3 energy levels, or elements after P, have access to an empty d-orbital. Because of this accessible d-orbital, the elements are exceptions to the octet rule. Elements in group 13 (column with B, Al, etc.) are also exceptions with 3 pairs of e-, rather than an octet.
by Nicholas_Gladkov_2J
Sat Nov 02, 2019 3:25 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 4
Views: 39

Re: Drawing Lewis Structures

What is the best way to know how to draw lewis structures and where to put double bonds or single bonds? For example, how do you know where to put double bonds in ClO4-? With drawing Lewis Structures, the most important things is to draw the proper amount of electrons and the placement of the atoms...
by Nicholas_Gladkov_2J
Sat Nov 02, 2019 3:16 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Minimizing Formal Charges
Replies: 5
Views: 55

Re: Minimizing Formal Charges

When you are finding the lewis structure with the least amount of energy, is the goal to minimize the formal energy of each of the different atoms or of the molecule as a whole. For example would you rather have three charges equal 0 and one equal 1 or would you rather have 2 charges equal 0, one e...
by Nicholas_Gladkov_2J
Fri Oct 25, 2019 11:37 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Calculating Subshells
Replies: 3
Views: 42

Re: Calculating Subshells

If you are given that n = 4 and want to get the amount of subshells there are, why is the final answer 4s, 4p, 4d, and 4f. I think you would first need to convert it to Angular Momentum, which you give you 3. Since 3 leaves you at the f-orbital, it means you'd have all those shells up to the f orbi...

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