Search found 107 matches

by Goyama_2A
Sat Mar 14, 2020 3:10 pm
Forum: Balancing Redox Reactions
Topic: Redox Reaction in a Basic Solution
Replies: 3
Views: 108

Re: Redox Reaction in a Basic Solution

yes, for redox reactions in basic solution, you are supposed to add H2O to the side of the reaction that needs more hydrogens and then balance accordingly by adding an equal number of moles of OH- to the other side.
by Goyama_2A
Sat Mar 14, 2020 2:45 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation Energies
Replies: 4
Views: 58

Re: Activation Energies

So, is a condition of a reaction having "arrhenius behavior" having constant activation energy?
by Goyama_2A
Sat Mar 14, 2020 1:51 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: lnA
Replies: 3
Views: 25

Re: lnA

ln A is based upon the variable A, which is called the pre-exponential factor. The pre-exponential factor represents the frequency of collisions between reactant molecules in a particular reaction.
by Goyama_2A
Sat Mar 14, 2020 1:47 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow and Fast Step
Replies: 7
Views: 99

Re: Slow and Fast Step

yes, when determining the overall rate of reaction, you can use the slow step as the sole determinant of the rate by assuming that the other steps are so fast in relation to the slow step that their influence on the overall reaction rate is negligible.
by Goyama_2A
Sat Mar 14, 2020 1:45 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation Energies
Replies: 4
Views: 58

Activation Energies

Are activation energies always constant? If not, what variables change them?
by Goyama_2A
Sun Mar 08, 2020 10:50 am
Forum: General Rate Laws
Topic: Rate law
Replies: 3
Views: 86

Rate law

The book explains that we sometimes need to specify the specific species our rate refers to or write our rate law as “rate of consumption/production of A” instead of just rate. When would we need to be specific with species/processes we are referring to?
by Goyama_2A
Sun Mar 08, 2020 10:47 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Checking Answers
Replies: 3
Views: 69

Checking Answers

The book mentioned that a good way to check your calculated rate constant when given experimental data is to plug it into the rate law with the given data and see if you get the given rate. I was wondering what some other quick ways there are to check our answers in this kinetics section?
by Goyama_2A
Sun Mar 08, 2020 10:43 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: determine n
Replies: 16
Views: 561

Re: determine n

n represents the order of the reactant, which in turn gives insight into the mechanism of the reaction. how do you know what the order is The order refers to the sum of all the exponents of the concentrations in the rate law. For example, if the rate law was rate=kr[A]^2[B]^3, the overall order wou...
by Goyama_2A
Sun Mar 08, 2020 10:40 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Terminology for reaction rate constant
Replies: 3
Views: 83

Re: Terminology for reaction rate constant

I believe that reaction rate constant and rate constant mean the same thing and can pretty much be used interchangeably, they will most likely always be referred to as one of the two. However, it is important to distinguish this from the reaction rate, which is the rate at any given moment in the re...
by Goyama_2A
Sun Mar 08, 2020 12:14 am
Forum: General Rate Laws
Topic: Units
Replies: 3
Views: 73

Units

the textbook gives units that your rate constants should be in for each reaction order, how do these work for non-whole number reaction orders?
by Goyama_2A
Sat Feb 29, 2020 10:41 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5G. 13
Replies: 2
Views: 54

Re: 5G. 13

The standard Gibbs of formation should only be used to calculate the delta G standard of a reaction at standard conditions (25C and 1 atm). If equilibrium isn't at those conditions, you should be using the given K to calculate the standard delta G of the reaction. In this case, they give you K so th...
by Goyama_2A
Sat Feb 29, 2020 10:35 pm
Forum: Balancing Redox Reactions
Topic: 6K.3 D)
Replies: 2
Views: 38

Re: 6K.3 D)

to your first question, I believe that Cl is acting as both a reducing and oxidizing agent because one of the Cls is giving an electron while the other is accepting that electron.
to your second question, I think someone told me that the Cl2 reactant is a typo and that it should be 2Cl
by Goyama_2A
Fri Feb 28, 2020 1:56 am
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: pH Electrodes, Corrosion, Etc
Replies: 2
Views: 33

Re: pH Electrodes, Corrosion, Etc

If those topics are reflected in the homework and/or lecture notes, they are fair game for test 2 so long as it is within the relevant section of thermodynamics or in our electrochemistry unit. I think the homework is probably a good indicator of what you should know regarding these, or any, topics.
by Goyama_2A
Fri Feb 28, 2020 1:52 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.1
Replies: 1
Views: 23

6M.1

The question asks to find the standard cell potential of (M2+/M) in the cell M(s)|M+ (aq)||Cu2+(aq)|Cu(s). I figured that since the cell has copper written on the right, that it was the cathode. But, the solutions manual treats the copper half reaction as the anode. How do we determine this?
by Goyama_2A
Fri Feb 28, 2020 1:48 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5G.17
Replies: 2
Views: 67

Re: 5G.17

To do this, you need to look at the relative rates of the product and reactant. You can see that I is being formed doubly as fast as I2 is being used up, due to the 1:2 ratio. To graph this, you just need to demonstrate this relationship using a graph of time on the x axis and concentration being on...
by Goyama_2A
Sun Feb 23, 2020 8:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5J.15
Replies: 3
Views: 65

Re: 5J.15

At different temperatures, delta G changes, which means that you cannot use the standard Gibbs free energy values at 100 degrees C, as those are only the values at 25 degrees C. This means in order to find the delta G at a different temperature, you would need to use the equation that relates delta...
by Goyama_2A
Sun Feb 23, 2020 6:25 pm
Forum: Balancing Redox Reactions
Topic: 6K.3 b)
Replies: 2
Views: 39

Re: 6K.3 b)

I think usually unless oxygen or hydrogen is written as it’s own molecule (I.e as shown in 6K.5A) we just put them as they are written in the half reactions of their respective molecules (I.e MnO4 - or H2SO3). They usually just allow us to determine the oxidation number of the species of focus.
by Goyama_2A
Sun Feb 23, 2020 6:22 pm
Forum: Balancing Redox Reactions
Topic: 6K.3 part d
Replies: 3
Views: 33

6K.3 part d

The problems asks to balance the redox reaction in acidic solution of : Cl2 (g) —> HClO (aq) + Cl2 (g) I understand why they broke the two reactions into Cl2 —> HClO and Cl2 —> 2Cl- But, I’m wondering why they were able to write the product in the second half reaction as chlorine ions (2Cl-) rather ...
by Goyama_2A
Sun Feb 23, 2020 1:40 pm
Forum: Balancing Redox Reactions
Topic: Balancing redox
Replies: 6
Views: 63

Balancing redox

How do you know which method to use when balancing half equations? I.e. balancing Hydrogens by adding H+ to one side vs balancing hydrogens by adding H2O to one side and OH- to the other.
What tells are there in a reaction that lets you know which way to go?
by Goyama_2A
Thu Feb 20, 2020 10:52 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5J.15
Replies: 3
Views: 65

5J.15

The question asks to calculate the equilibrium constant at 23 C and 100 C for two reactions using the data from appendix 2A. Even though the standard Gibbs of formation for the molecules is given in the appendix, the solutions manual says we have to use the enthalpies of formation and entropies of f...
by Goyama_2A
Wed Feb 12, 2020 12:07 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Delta S total vs regular delta S
Replies: 1
Views: 33

Re: Delta S total vs regular delta S

deltaS total is the sum of the delta S of the surroundings and the delta S of the system. Typically, when there is no subscript for a variable, as is the case with just delta S, that means it is referring to the system. So, deltaS is just the change in entropy of the system.
by Goyama_2A
Wed Feb 12, 2020 12:04 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Adiabatic
Replies: 2
Views: 40

Re: Adiabatic

when a system is adiabatic, there is no heat flow meaning:
q=0
deltaU=w
by Goyama_2A
Wed Feb 12, 2020 12:00 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Cp and Cv
Replies: 2
Views: 42

Re: Cp and Cv

pretty much anytime the substance is an ideal gas in a problem and the C isn't explicitly given to you, you'll use either (3/2)R or (5/2)R to calculate q. Under conditions of constant volume, you would use the (3/2)R and under conditions of constant pressure, you would use (5/2)R.
by Goyama_2A
Tue Feb 11, 2020 11:52 pm
Forum: Calculating Work of Expansion
Topic: Midterm Q
Replies: 1
Views: 52

Re: Midterm Q

I believe you should know the meanings of the two terms as they might be used in an equation:
isobaric- constant pressure
isochoric- constant volume
isothermal- constant temperature

understanding these terms is important because they influence the values and calculations used in a problem
by Goyama_2A
Tue Feb 11, 2020 11:50 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Phase change’s effect on entropy
Replies: 1
Views: 24

Re: Phase change’s effect on entropy

I believe this statement refers to the equation for gibbs free energy (deltaG=deltaH- TdeltaS). This means that the magnitude of influence the deltaS, entropy, has on the change in Gibb's free energy is dependent on T. This is because, as T increases, because it is being multiplied by deltaS, the ma...
by Goyama_2A
Tue Feb 11, 2020 11:44 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Homework Question 4I.1
Replies: 2
Views: 31

Re: Homework Question 4I.1

Yes, you would use that method. The reasoning behind this is that entropy is a state function, so the value is only dependent on its final state rather than the path taken to get there. Because of this, you are able to add together the change in entropy from each step and find the change in entropy ...
by Goyama_2A
Tue Feb 11, 2020 11:39 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Homework 4J.7
Replies: 1
Views: 32

Re: Homework 4J.7

I used the enthalpy of formation and gibbs free energy of H2O (l). The appendix doesn't even list an H2O aqueous. I see where you're looking, but the solutions manual used the values listed under H2O (l) despite writing H2O (aq) so it might've been a typo.
by Goyama_2A
Mon Feb 10, 2020 2:42 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible vs. Irreversible reactions
Replies: 1
Views: 26

Reversible vs. Irreversible reactions

I know that work is different for reversible and irreversible reactions, so how does my calculation of work differ for a reversible vs. an irreversible reaction? Additionally, what other values/calculations differ for reversible vs. irreversible reactions and how do I accommodate those differences (...
by Goyama_2A
Thu Feb 06, 2020 5:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.9
Replies: 1
Views: 47

4D.9

The questions asks to find the enthalpy change per liter for the reaction TNT and O2 to form CO2, H2O, and N2. I understand how they used the enthalpies of formation to find the enthalpy of the reaction to be -13168 kJ/mol. But, when they divide that by 4 to get the delta H per mole of TNT, they mak...
by Goyama_2A
Wed Feb 05, 2020 8:56 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Change in entropy for a monatomic ideal gas vs diatomic molecules
Replies: 3
Views: 127

Re: Change in entropy for a monatomic ideal gas vs diatomic molecules

As more atoms are in a molecule, the number of microstates (possible arrangements) increase and thus there are overall more ways to distribute the motional energy of the molecules within the gas sample. In lecture, Dr. Lavelle uses the number of microstates as the primary indication of change in ent...
by Goyama_2A
Wed Feb 05, 2020 8:48 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Microstates
Replies: 7
Views: 63

Re: Microstates

Microstates are the varying possible arrangements for molecules. As motional energy (ie rotational, transitional, and vibrational energy discussed in the textbook pg.260) increases, the number of microstates tends to increase as well, which, in lecture, we take as a conceptual indication as a positi...
by Goyama_2A
Wed Feb 05, 2020 8:41 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy of formation
Replies: 2
Views: 29

Re: enthalpy of formation

I believe so.
This is the case for most because no change is occurring in the reaction:
ie. O2–>O2
However, if you were to calculate the enthalpy change in a reaction such as:
2O—> O2
You would be calculating the heat of atomization(which is the heat released when the O2 bond is formed)
by Goyama_2A
Wed Feb 05, 2020 7:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy
Replies: 2
Views: 33

Enthalpy

I was doing problem 4C.3 and in the solution they said that at constant pressure, change in enthalpy is equal to q. Why is this?
by Goyama_2A
Thu Jan 30, 2020 7:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test #1// #5
Replies: 5
Views: 73

Re: Test #1// #5

I had a different form but the gist should be the same. Use the given Molarity of hydrogen fluoride to set up an ICE table. Once that's set up, you should have equilibrium concentrations in terms of X. Use the equilibrium concentration values in terms of x to create an equation for the equilibrium c...
by Goyama_2A
Thu Jan 30, 2020 7:27 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Equipartition Theorem
Replies: 2
Views: 28

Re: Equipartition Theorem

Since it wasn't addressed in lecture, you won't be expected to know it. But, I think it'll be helpful to understand the foundations that go into forming the theorem.
by Goyama_2A
Thu Jan 30, 2020 7:24 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: When do we need to consider the calorimeter?
Replies: 2
Views: 34

Re: When do we need to consider the calorimeter?

Unless the question specifically states that you're considering the calorimeter as a system or as surroundings, I think it isn't counted as either. The main contribution of a calorimeter in a problem is its measurements of heat absorbed or released by a system.
by Goyama_2A
Thu Jan 30, 2020 7:12 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Value of q
Replies: 11
Views: 127

Re: Value of q

In lecture, Dr.Lavelle showed us that perfect system equation which states that q(system)+q(surroundings)=0, which in turn means that q(system)=-q(surroundings) or vice versa.
by Goyama_2A
Thu Jan 30, 2020 7:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1 Problem 5
Replies: 1
Views: 35

Re: Test 1 Problem 5

I think you would use the given molarity value of the triethylamine solution to make an ICE table. The equilibrium value for the N(CH3CH2)3, NH(CH3CH2)3+, and the OH- should come out to 0.2-x, x, and x respectively. Then use those equilibrium values to make an equation for the equilibrium constant t...
by Goyama_2A
Mon Jan 20, 2020 2:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Van’t Hoff Equation
Replies: 4
Views: 60

Van’t Hoff Equation

What do the vant hoff equation variables mean and what is it used for? Are we expected to use this equation? If so, in what scenario might we use it?
by Goyama_2A
Mon Jan 20, 2020 1:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: K value at a specific temp
Replies: 6
Views: 76

K value at a specific temp

In the “skills you have mastered” section of 5J, it says we should be able to predict the value of K at one temperature from its value at another temperature. Lavelle excluded part of this section from the assigned reading, but I just wanted to make sure. Should we be able to do this? Have we addres...
by Goyama_2A
Mon Jan 20, 2020 1:46 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE table
Replies: 3
Views: 70

Re: ICE table

X is assigned to Change in molarity based on the balanced equilibrium reaction. In 5I.15, the reaction is 1:1:1 meaning all changes should either be +x or -x. If the reaction had a different ratio then the changes would be reflective of that ratio. Consider the equation 1AB2C2 —> 1A + 2BC. Since the...
by Goyama_2A
Mon Jan 20, 2020 1:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5 percent rule
Replies: 2
Views: 19

Re: 5 percent rule

The 5% rule basically allows us to determine the validity of an approximation by looking at the percent of ionization of the acid. Consider the reaction: [HA] —> [H+] + [A-]. If you’re looking for the Ka value, you’d need to use the equation Ka= x^2/([HA] - x). But, if the Ka is very small (Lavelle ...
by Goyama_2A
Mon Jan 20, 2020 1:19 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas
Replies: 6
Views: 70

Re: Inert Gas

When talking about the effect of inert gases on a reaction at equilibrium, we are more focused on the fact that it is extremely stable and thus does not react. The inert gas wouldn’t interact significantly with the other reactants/products in the reaction and this has no net effect on the direction ...
by Goyama_2A
Sun Jan 19, 2020 8:52 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: homework 5G9
Replies: 1
Views: 15

Re: homework 5G9

So for these, you’re going to use your understanding of fundamental concepts and Le Chateliers to decide if they’ll stay the same or change: A) the amount of O2 will be different because there are different amounts of reactants and this different amounts of products B) the partial pressure of O2 sho...
by Goyama_2A
Thu Jan 16, 2020 7:21 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Acids and Bases, understanding the Ka value
Replies: 3
Views: 94

Re: Acids and Bases, understanding the Ka value

A larger Ka indicates a stronger acid, meaning the acid ionizes more than if it had a smaller Ka. So, that means the bonds in the acid are weak because they are more inclined to dissociate.
by Goyama_2A
Thu Jan 16, 2020 7:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Neutral Solutions
Replies: 1
Views: 13

Neutral Solutions

At the end of the last lecture, Dr.Lavelle explained that if [H3O+]<10^-7 then the solution is considered neutral, could someone explain why this is?
by Goyama_2A
Thu Jan 16, 2020 7:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.19
Replies: 2
Views: 22

Re: 6A.19

I believe that that is just a typo on the part of the solutions manual because, in order to get the OH- concentration, you just need to divide Kw (1x10^-14) by the respective H3O+ concentration, which they did correctly in all of the other parts. The answer I got is 3.23x10^-15.
by Goyama_2A
Thu Jan 16, 2020 6:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Converting between K and Kc
Replies: 2
Views: 32

Converting between K and Kc

In the book, they give an equation for converting between Kc and K: . How do I use this equation? Does Lavelle expect us to be able to practice this equation?
by Goyama_2A
Thu Jan 09, 2020 4:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constants with Ionic Compounds
Replies: 2
Views: 28

Equilibrium Constants with Ionic Compounds

The book mentions that, in reactions involving fully dissociated ionic compounds in solution, the equilibrium constant should be written for the net ionic equation by using the activity for each type of ion. First off, what does this fully mean in simpler terms? and is this something we should be do...
by Goyama_2A
Thu Jan 09, 2020 3:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp v. Kc
Replies: 5
Views: 39

Re: Kp v. Kc

If the way the equilibrium constant was calculated is in no other way indicated, it is safe to assume that the K value was calculated using whatever form of given concentrations/partial pressures is in the question (meaning if they give you a partial pressure, it is probably Kp and vice versa). Plus...
by Goyama_2A
Thu Jan 09, 2020 3:56 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: determining shift in equilibrium
Replies: 4
Views: 37

Re: determining shift in equilibrium

Because the change in energy is negative, the reaction is exothermic. The answer is that the reaction shifts to the left because the reaction is exothermic and thus decreasing temperature would move the reaction in the forward. Therefore, increasing temperature would do the opposite.
by Goyama_2A
Thu Jan 09, 2020 3:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solid/liquid
Replies: 7
Views: 48

Re: solid/liquid

when writing the K expression, you don't include it. But say the solid or liquid is the only product in the reaction, you'd still put a 1 in the numerator over your non-solid/liquid reactants.
by Goyama_2A
Thu Jan 09, 2020 3:52 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: calculating the equilibrium concentrations of products and reactants
Replies: 1
Views: 51

Re: calculating the equilibrium concentrations of products and reactants

First off, since the initial concentration of SO3 is 0 and you are adding 2X, the equilibrium concentration should only be 2X rather than c+2X. You would then proceed using your equilibrium equations you have set up (0.522-2X, 0.633-X, and 2X) in filling out your equation for K. With these equilibri...
by Goyama_2A
Sun Dec 08, 2019 11:19 am
Forum: Air Pollution & Acid Rain
Topic: Blood pH [ENDORSED]
Replies: 1
Views: 81

Blood pH [ENDORSED]

What are the roles that CO2, H2CO3, and HCO3- play in maintaining blood at a pH of 7.4? Lavelle said to look for it in the textbook but I was unable to find it.
by Goyama_2A
Sun Dec 08, 2019 11:18 am
Forum: Conjugate Acids & Bases
Topic: Bronsted vs Conjugate
Replies: 3
Views: 133

Re: Bronsted vs Conjugate

A bronsted acid is something that in it of itself is a proton donor. A conjugate acid is the acid resulting after a bronsted base accepts a proton. For example, NH4+ is the conjugate acid of NH3.
by Goyama_2A
Sun Dec 08, 2019 12:57 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxalate
Replies: 2
Views: 119

Oxalate

Why is oxalate bidentate and not tetradentate?
by Goyama_2A
Sun Dec 08, 2019 12:54 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ph and poH of weak acids
Replies: 8
Views: 92

Re: Ph and poH of weak acids

No, 14a no longer requires student to do calculations based on weak acids and bases. I think we’ll learn more about that in 14B.
by Goyama_2A
Sun Dec 08, 2019 12:53 am
Forum: Air Pollution & Acid Rain
Topic: Options to reduce acid rain
Replies: 7
Views: 165

Re: Options to reduce acid rain

You should know the reactions behind acid rain. Acid rain is largely contributed to the interactions of water with nitrogen and sulfur oxides. So, solutions to acid rain would pretty much be anything reducing human activity causing the excessive release of sulfur and nitrogen into the environment. T...
by Goyama_2A
Wed Nov 27, 2019 4:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinate covalent bonds
Replies: 4
Views: 56

Coordinate covalent bonds

What make a coordinate covalent bond differ from an ionic or covalent? I understand that, in coordinate covalent bonds, both electrons are donated by the same atom, but if that’s the case, how do they differ from ionic bonds?
by Goyama_2A
Wed Nov 27, 2019 4:44 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: polydente
Replies: 2
Views: 48

Re: polydente

Unless you know by memorizing a specific coordination compound, I don’t think you can just determine by looking at the formula. Drawing it out helps because it shows you the placement of the atoms and the compound’s structure.
by Goyama_2A
Wed Nov 27, 2019 4:43 pm
Forum: Amphoteric Compounds
Topic: Amphoteric Compounds other than Be, Al, Ga, Sn, Pb, and Sb
Replies: 3
Views: 48

Re: Amphoteric Compounds other than Be, Al, Ga, Sn, Pb, and Sb

I don’t think there is any set steps to determining whether or not something is amphoteric. However, it is helpful to think about the conjugate base and/or acid of something in determine whether it is amphoteric. If something doesn’t have a Hydrogen atom, it obviously doesn’t have a proton to donate...
by Goyama_2A
Wed Nov 27, 2019 4:36 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Relative Acidity (Noting a strong acid)
Replies: 1
Views: 28

Re: Relative Acidity (Noting a strong acid)

The trichloroacetic acid is stronger because the chlorine is an electron withdrawing group. This causes a withdrawal of electrons from both the carbon atom and the oxygen atom. Due to the withdrawal of electrons, the electron density in the O-H bond is diminished and this weakens the O-H bond, this ...
by Goyama_2A
Wed Nov 27, 2019 3:26 pm
Forum: Lewis Acids & Bases
Topic: Bronsted and Lewis Acids
Replies: 4
Views: 60

Re: Bronsted and Lewis Acids

Bronsted acids/bases focuses on the protons:
-bronsted acids- proton donors
-bronsted bases- proton acceptors

Lewis acids/bases focus on the electrons:
-Lewis acids- electron pair acceptor
-Lewis bases- electron pair donor
by Goyama_2A
Sun Nov 24, 2019 12:24 pm
Forum: Naming
Topic: HW problem 9C.3(d)
Replies: 2
Views: 45

Re: HW problem 9C.3(d)

I believe the rule is to write the neutral molecule first and then the anion. If there are multiple anions, they are listed in order of their atomic numbers.
by Goyama_2A
Sun Nov 24, 2019 12:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Hybridization
Replies: 7
Views: 76

Hybridization

What is the purpose of hybridization? Why does it occur?
by Goyama_2A
Sun Nov 24, 2019 12:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Identifying Polydentate Ligands
Replies: 5
Views: 47

Re: Identifying Polydentate Ligands

When determining whether or not a ligand is polydentate, you need to look at the location of lone pairs on the ligand and the shape of the ligand. If the lone pair locations are spread out between several atoms on a ligand, it is likely to be polydentate rather than when they are all located on one ...
by Goyama_2A
Sun Nov 24, 2019 12:00 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: homework
Replies: 3
Views: 52

Re: homework

I believe it also should include hybridization because that wasn’t a topic covered on our most recent test.
by Goyama_2A
Sun Nov 24, 2019 11:57 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Why are inorganic acids stronger?
Replies: 8
Views: 109

Re: Why are inorganic acids stronger?

The strength of an acid is based upon its ability to lose hydrogen ions (ionize) when dissolved in water. Inorganic compounds lose hydrogens ions much more easily than organic, making them considered stronger.
by Goyama_2A
Wed Nov 20, 2019 10:36 am
Forum: Hybridization
Topic: electron promotion
Replies: 1
Views: 25

Re: electron promotion

Yes I believe it can be any atom that has an empty p orbital and a paired s orbital.
by Goyama_2A
Sun Nov 17, 2019 12:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 5
Views: 62

Re: Lone Pairs

No, depending on the bonds and number of lone pairs that are also arranged about the central atom, a molecule with lone pairs can hold a wide variety of molecular shapes.
by Goyama_2A
Sun Nov 17, 2019 12:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair location
Replies: 3
Views: 49

Lone Pair location

Why in some molecular shapes (like square planar) are the lone pairs on opposite sides of the central atom but in other molecular shapes (like bent or t-shape) the lone pairs are next to one another? How do you determine where the lone pairs are in relation to one another about the central atom?
by Goyama_2A
Sun Nov 17, 2019 12:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 6
Views: 75

Re: VSEPR

The valence shell electron repulsion theory is the model by which we determine molecular shapes by determining the form of the molecule which would minimize the electrostatic repulsion. This helps us to determine shapes because our Lewis structures tell us the bonds and line pairs in a molecule but ...
by Goyama_2A
Sun Nov 17, 2019 12:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.25
Replies: 2
Views: 34

Re: 2E.25

The lone pair causes the S-F bonds to not be directly symmetrical from one another and therefore their dipole moments don’t cancel out.
by Goyama_2A
Sun Nov 17, 2019 12:37 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures (Multiple Atoms)
Replies: 3
Views: 58

Re: Drawing Lewis Structures (Multiple Atoms)

Usually it helps to know which atom will be the central atom. The central atom is the atom with the least electronegativity (except in cases where that atom is hydrogen). From there, you could just go about arranging the remaining atoms about the central.
by Goyama_2A
Sun Nov 10, 2019 2:31 am
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 3
Views: 38

Dipole Moments

What is a dipole moment and how do they affect intermolecular forces?
by Goyama_2A
Sun Nov 10, 2019 2:26 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electron Transitions
Replies: 2
Views: 118

Re: Electron Transitions

So for this problem, you could’ve used the rydberg formula to find energy at a specific level. I believe they gave us the change in energy, so you’d use the delta E= E(final) - E(initial). The only variable you should have left in the formula would be n(final) because they told us that it was a hydr...
by Goyama_2A
Sun Nov 10, 2019 2:21 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarisability and Size
Replies: 3
Views: 56

Re: Polarisability and Size

I think I remember Lavelle explaining it as those larger molecule have more electrons, resulting in stronger London dispersion forces due to the fact that they have stronger instantaneous-induced dipoles.
by Goyama_2A
Sun Nov 10, 2019 2:16 am
Forum: Dipole Moments
Topic: Homework Problem 3F.15
Replies: 1
Views: 41

Re: Homework Problem 3F.15

If you were trying to determine the answer to this question using Lewis structures, you would have to look at the molecular shapes. The AsF3 molecule has lone pairs pushing the three bonds down, this giving it a pyramidal shape, which is polarized as the less electronegative atom is on one side whil...
by Goyama_2A
Sun Nov 10, 2019 2:09 am
Forum: Photoelectric Effect
Topic: Wavelength from Work Function
Replies: 1
Views: 148

Re: Wavelength from Work Function

Assuming you’re talking about the wavelength of light, you would use the E= Kinetic Energy + work function formula in order to find the energy of the photon. I believe I remember the question asking for the wavelength of the photon which emitted the electron. If you’re looking for the wavelength of ...
by Goyama_2A
Tue Nov 05, 2019 10:21 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: Schrodingers Equation
Replies: 1
Views: 28

Schrodingers Equation

Can someone please explain the basic concepts we should know for schrodinger’s equation? It confuses me so much
by Goyama_2A
Sat Nov 02, 2019 11:25 am
Forum: Bond Lengths & Energies
Topic: Bonding
Replies: 7
Views: 104

Bonding

What are the general exceptions to the octet rule we should know? And how many electrons can those exceptions hold when bonding?
by Goyama_2A
Sat Nov 02, 2019 11:17 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Understanding Ionic Radius
Replies: 3
Views: 53

Re: Understanding Ionic Radius

Yes, as elements move to the right in a period, they have more protons, resulting in a high effective nuclear charge (in other words, a stronger pull) on each electron from the nucleus. This stronger pull leads to a smaller radius.
by Goyama_2A
Sat Nov 02, 2019 11:13 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Energy of orbitals
Replies: 2
Views: 38

Re: Energy of orbitals

The energy of an orbital refers to the amount of energy required of electrons to be in that orbital. In order for an electron to be in a certain orbital, it must have the discrete amount of energy required of that orbital. This higher energy is due to the fact that the higher energy orbitals are fur...
by Goyama_2A
Sat Nov 02, 2019 11:08 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron configuration rules
Replies: 1
Views: 36

Re: Electron configuration rules

Pauli’s principle states two things: there can be no more than 2 electrons in an orbital and electrons in the same orbital must be spin paired. This would be violated if you placed 3 electrons or more in an orbital or if your 2 electrons had the same direction of spin (ie both +1/2 or both -1/2). Hu...
by Goyama_2A
Sat Nov 02, 2019 10:57 am
Forum: Octet Exceptions
Topic: Odd number of valence electrons
Replies: 2
Views: 47

Re: Odd number of valence electrons

The electron is usually placed in a way that would allow our structure to be the lowest energy structure, meaning the least formal charges possible. So, it’s mostly the same as any other situation where you’re trying to figure out the best structure for bonding, except this time you happen to have a...
by Goyama_2A
Sun Oct 27, 2019 2:25 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 8
Views: 71

Re: Resonance

Resonance is the blending of structures with the same arrangement of atoms but different arrangements of electrons. The actual structure is a hybrid of these resonant structures and is the most stable structure. The resonant structures all have the same energy and allow us to both visual and predict...
by Goyama_2A
Sun Oct 27, 2019 2:15 pm
Forum: Ionic & Covalent Bonds
Topic: Valence Electrons
Replies: 4
Views: 47

Re: Valence Electrons

When counting the number of valence electrons an element has, you only count the number of electrons held in the outer shell. This usually doesn’t include those from the d-orbital because electrons aren’t placed in the d-orbital until there are some in the next shell s-orbital, but by then the s-orb...
by Goyama_2A
Fri Oct 25, 2019 11:04 am
Forum: Ionic & Covalent Bonds
Topic: Ionization Energy
Replies: 5
Views: 56

Re: Ionization Energy

When thinking about ionization energy comparisons between several elements, you have to take both the period and the group into account rather than just the groups. Therefore the ionization energy trends can’t just be described with one direction, such as down. The ionization energy increases in the...
by Goyama_2A
Fri Oct 25, 2019 10:57 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Sulfur bonding
Replies: 5
Views: 57

Re: Sulfur bonding

Although most elements need exactly 8 electrons in a bond to be stable, there are some exceptions to the rule. Some elements, like Boron, can be stable with less than 8 electrons, while some other elements, like Sulfur, can be stable with more than 8 electrons. This is due to the expansion of valenc...
by Goyama_2A
Fri Oct 25, 2019 10:43 am
Forum: Electronegativity
Topic: Molecular Geometry
Replies: 4
Views: 79

Re: Molecular Geometry

The topic hasn’t really been brought up yet in specifics as to the shapes, so as of what we have learned so far, probably not. But, if it’s addressed by the midterm then yes.
by Goyama_2A
Sun Oct 20, 2019 5:10 pm
Forum: DeBroglie Equation
Topic: DeBroglie Equation
Replies: 11
Views: 147

Re: DeBroglie Equation

You use de Broglies equation to find the wavelength of an object with mass when given the mass and velocity of the object. The units for the equation are: Joules•seconds for plancks constant, kg for mass, meters/second for velocity, and meters for wavelength.
by Goyama_2A
Sun Oct 20, 2019 4:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework week 4
Replies: 4
Views: 56

Re: Homework week 4

yes, our homework is to be done on the topic we are currently working on. So since we are still on quantum world, you just pick five other problems from the topic to turn in.
by Goyama_2A
Sun Oct 20, 2019 4:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: Matter and wavelike properties
Replies: 3
Views: 49

Re: Matter and wavelike properties

Wavelength is inversely proportional to mass. This means that, the higher the mass, the shorter the wavelength. For larger objects, the wavelength becomes so small (the rule is generally any wavelength less than 10^-15 m) that it is unnoticeable. We just have to assume that it have wavelike properti...
by Goyama_2A
Sun Oct 20, 2019 4:38 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty in Speed
Replies: 2
Views: 41

Re: Uncertainty in Speed

The uncertainty in velocity would be 10 m/s. The uncertainty is given by the total range of what it could be. So, in this case, since the velocity could be anywhere ranging from 0 m/s to 10 m/s, your uncertainty in velocity would be 10 m/s.
by Goyama_2A
Sun Oct 20, 2019 4:36 pm
Forum: Properties of Electrons
Topic: Mass of an Electron
Replies: 14
Views: 230

Re: Mass of an Electron

This is a set mass. Electrons don’t gain or lose mass through any process. It is given to us on our constant sheet.
by Goyama_2A
Sun Oct 20, 2019 4:33 pm
Forum: Properties of Electrons
Topic: Hund's Rule
Replies: 5
Views: 88

Re: Hund's Rule

Hund’s Rule basically states that, due to electron repulsion, each orbital in a sub shell is occupied by a single electron before any electrons within that orbital are paired. It also explains that each of the single electrons have the same spin. The rule helps us to figure out electron configuratio...
by Goyama_2A
Sun Oct 13, 2019 8:26 pm
Forum: Properties of Light
Topic: Electron energy levels
Replies: 2
Views: 43

Electron energy levels

Why can’t electrons exist between energy levels? I remember Lavelle mentioning this in class but I’m confused as to why
by Goyama_2A
Sun Oct 13, 2019 8:20 pm
Forum: Significant Figures
Topic: Tests and Significant Figures
Replies: 6
Views: 216

Re: Tests and Significant Figures

On the class website, there’s a list of a bunch of helpful links and one of them is titled “everything you want to know about sig fig” which is a document with all of the sig fig rules and I’m assuming Lavelle accepts these rules.
by Goyama_2A
Sun Oct 13, 2019 8:17 pm
Forum: Properties of Light
Topic: SI units
Replies: 3
Views: 26

Re: SI units

Lavelle has chemistry constants and equation documents listed on the class website and they have helpful information for conversions and constants.

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