Search found 120 matches

Thu Mar 12, 2020 11:13 am
Forum: Zero Order Reactions
Topic: Example Help
Replies: 6
Views: 171

Re: Example Help

If you see a graph of [A] v. t and it is linear with a negative slope, you know that the reaction is zero-order with respect to that reactanct. The rate constant k is equal to the negative of the slope.
Thu Mar 12, 2020 11:05 am
Forum: Second Order Reactions
Topic: Graphs
Replies: 7
Views: 159

Re: Graphs

A first-order reaction will have a straight-line graph of ln[A] v. t A second-order reaction will have a straight-line graph of 1/[A] v. t A zero-order reaction will have a straight-line graph of [A] v. t The first-order and zero-order graphs will have negative slopes while the second-order graph wi...
Thu Mar 12, 2020 9:50 am
Forum: Zero Order Reactions
Topic: Orders
Replies: 8
Views: 128

Re: Orders

I believe that if we need to determine the order of a reaction based on graphs, then they will most likely provided the graphs that we need.
Thu Mar 12, 2020 9:34 am
Forum: General Rate Laws
Topic: Units
Replies: 4
Views: 92

Re: Units

The unit for the rate constant will depend on the overall reaction order. The rate will always be in units of M/s and each concentration will be in M. So the rate constant will always be in units so that when multiplied with the concentrations, the result will be in M/s.
Thu Mar 12, 2020 9:22 am
Forum: *Enzyme Kinetics
Topic: How to distinguish the intermediates and catalysts?
Replies: 8
Views: 158

Re: How to distinguish the intermediates and catalysts?

An intermediate will first appear as a product and then appear again as a reactant. Catalysts are the opposite. They will first appear as a reactant and then appear again as a product. Note than neither intermediates nor reactants will show up in the overall balanced equation.
Tue Mar 10, 2020 12:46 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Work and Delta G
Replies: 4
Views: 53

Re: Work and Delta G

Generally, I believe the maximum amount of work able to be done (wmax) is equal to deltaG. This is for all reactions under any conditions I believe.
Fri Mar 06, 2020 1:41 am
Forum: Balancing Redox Reactions
Topic: Values of Andode and Cathode
Replies: 8
Views: 167

Re: Values of Andode and Cathode

A table of values of standard reduction potentials should be provided if they are needed to solve a particular problem.
Fri Mar 06, 2020 1:35 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Electrode masses
Replies: 8
Views: 125

Re: Electrode masses

The cell potential will not change because the electrodes are solids, so increasing their masses will not impact the chemical equilibrium. However, as the previous post noted, increasing the mass of an electrode will prolong the battery's life while decreasing the mass will shorten the battery's life.
Fri Mar 06, 2020 1:28 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Potentials
Replies: 4
Views: 87

Re: Standard Potentials

I don't think that knowing this is super important or essential, but it is good to know. The standard reduction potentials are all based on reactions with the standard hydrogen electrode as a common reference point.
Fri Mar 06, 2020 1:24 am
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Electrolytic Cells
Replies: 1
Views: 115

Re: Electrolytic Cells

An electrolytic cell has a negative cell potential. Therefore, if you know the two half-reactions, you can arrange them in a way that results in the cell potential being negative.
Thu Mar 05, 2020 12:09 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: reduction and oxidation
Replies: 4
Views: 68

Re: reduction and oxidation

The species that is reduced is the one with the more positive standard reduction potential. The species that is oxidized is the one with the more negative standard reduction potential. This set-up will result in a positive cell potential.
Thu Mar 05, 2020 12:05 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: strength as reducing agents
Replies: 3
Views: 55

Re: strength as reducing agents

You can find standard reduction potentials in the back of the book in Appendix 2B.
Thu Feb 27, 2020 3:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: How to tell which is anode/cathode based on standard reduction potentials E
Replies: 5
Views: 48

Re: How to tell which is anode/cathode based on standard reduction potentials E

Yes, if you want to have a positive cell potential overall, the more positive E will be at the cathode and the less positive E will be at the anode.
Thu Feb 27, 2020 10:49 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: water in the equilibrium constant
Replies: 2
Views: 45

Re: water in the equilibrium constant

Water is only included in the equilibrium constant expression when it is in the gas phase. Solids and liquids are not included when calculating equilibrium constants.
Thu Feb 27, 2020 12:38 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrodes of Galvanic Cells
Replies: 2
Views: 42

Re: Electrodes of Galvanic Cells

I believe that an electrode has to be solid metal, not just any solid. Some solids are not metal, and I do not think these would work as electrodes.
Thu Feb 27, 2020 12:35 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: When to use anode/cathode not in the reaction
Replies: 3
Views: 45

Re: When to use anode/cathode not in the reaction

You need to use a platinum metal electrode for the cathode/anode when there is no solid metal conductor present in the redox reaction. The platinum electrode allows for electron transfer without affecting the actual redox reaction.
Wed Feb 26, 2020 4:36 pm
Forum: Balancing Redox Reactions
Topic: 6L.3
Replies: 1
Views: 57

Re: 6L.3

In that cell notation, the species on the right of the double line are reacting at the cathode. Since reduction occurs at the cathode end of the cell, you know that Cl2 is the one being reduced.
Wed Feb 26, 2020 4:27 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Pt(s) use
Replies: 5
Views: 93

Re: Pt(s) use

A platinum electrode is needed when there is no solid metal conductor as an electrode already present. If there are already a metal anode and a metal cathode, then the platinum electrode is unnecessary. Whenever an inert electrode is needed, it is usually the platinum electrode, and I am unsure if t...
Sun Feb 23, 2020 12:32 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: cell potention in nernst
Replies: 3
Views: 52

Re: cell potention in nernst

In addition, Eo is a value that has been found experimentally and is commonly found in tables, not requiring calculations. However, E is the cell potential at any condition and requires calculations to find. Eo is used in the Nernst Equation to find E.
Sun Feb 23, 2020 12:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Conductors vs. Nonconductors
Replies: 3
Views: 53

Re: Conductors vs. Nonconductors

The reason we had to include a platinum electrode in this example is because both Fe3+ and Fe2+ are in solution. This means that there is no solid metal electrode present. The platinum electrode was needed in order for electrons to flow from anode to cathode.
Sun Feb 23, 2020 12:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic/Voltaic cells
Replies: 3
Views: 43

Re: Galvanic/Voltaic cells

I'm sure there are some features in the batteries we use every day that allow for charged particles to move freely and prevent charge buildup. Even if it is not a salt bridge, the mechanism likely has the same purpose.
Sun Feb 23, 2020 12:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: platinum
Replies: 4
Views: 51

Re: platinum

Platinum is commonly used as an electrode when the reaction at the cathode or anode does not have a conducting solid metal involved. Platinum is used because it is an inert metal and will not directly affect the redox reaction.
Sun Feb 23, 2020 12:08 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: test 2 material clarification
Replies: 10
Views: 169

Re: test 2 material clarification

Yes, these topics will be covered on Test 2. Test 2 is on the second page of the thermodynamics outline and electrochemistry.
Sun Feb 23, 2020 12:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 89

Re: salt bridge

In a galvanic cell, a salt bridge allows charged particles to pass from one beaker to another to prevent charges from building up. If charges were allowed to build in the beakers, the redox reaction would stop prematurely due to charge buildup.
Mon Feb 10, 2020 11:16 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: q vs delta H
Replies: 2
Views: 36

Re: q vs delta H

q is the same as deltaH under conditions of constant pressure. Enthalpy is defined as the amount of heat released or absorbed at a constant pressure.
Mon Feb 10, 2020 11:10 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pKb to pOH
Replies: 2
Views: 30

Re: pKb to pOH

Depending on if the question was dealing with a weak acid or a weak base, you would first need to calculate Ka (for an acid) or Kb (for a base). Then, you would need to set up and solve an ICE table using the reaction between the acid/base and water. After that, you should have either [H 3 O + ] or ...
Mon Feb 10, 2020 8:52 pm
Forum: Calculating Work of Expansion
Topic: calculating work of a reversible reaction
Replies: 5
Views: 96

Re: calculating work of a reversible reaction

Work will be negative when the system does work on the surroundings. This generally happens when the system expands in volume through work of expansion.
Mon Feb 10, 2020 8:50 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Delta S sub m
Replies: 2
Views: 31

Re: Delta S sub m

The "m" stands for molar, which means that the whole term refers to the entropy of one mole of the given substance.
Mon Feb 10, 2020 8:46 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 4D.7
Replies: 1
Views: 21

Re: 4D.7

I think when the temperature is not given explicitly, you can assume it is 298 K if it's needed for the problem. I think this also applies to pressure, and we assume it is 1.00 atm.
Mon Feb 10, 2020 8:42 pm
Forum: Calculating Work of Expansion
Topic: 4B.13 B finding moles
Replies: 1
Views: 29

Re: 4B.13 B finding moles

When temperature, pressure, and volume are given in a problem, you can solve for moles using the equation PV=nRT. The gas constant (R) is provided on the constants and equations sheet.
Fri Feb 07, 2020 10:01 pm
Forum: Calculating Work of Expansion
Topic: Equation for Work
Replies: 3
Views: 29

Re: Equation for Work

Yes, the equation will still have a negative sign in front. When work is done on the system, the change in volume is negative. This negative cancels with the one in the equation, resulting in a positive value for work. This makes sense because when work is done on the system, the value should be pos...
Fri Feb 07, 2020 9:14 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Question 4B.3
Replies: 5
Views: 64

Re: Question 4B.3

In the solution manual that I have, 490 J is the correct answer. It is written as 4.90*102 J, but it is still the correct answer.
Thu Feb 06, 2020 9:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 4B.13a
Replies: 3
Views: 47

Re: 4B.13a

This constant is used to convert between L*atm and Joules. It can be found on the provided constants & equations sheet.
Thu Feb 06, 2020 8:45 pm
Forum: Phase Changes & Related Calculations
Topic: Heating Curve
Replies: 3
Views: 57

Re: Heating Curve

If the heating curve is steeper, that means that the specific heat capacity for that material is low. Since the curve is steep, that means that it does not take much energy to raise the temperature of the material. Conversely, a curve that is not steep means that the specific heat capacity for that ...
Thu Feb 06, 2020 8:38 pm
Forum: Calculating Work of Expansion
Topic: Isothermal
Replies: 17
Views: 198

Re: Isothermal

The word "isothermal" refers to a system being at a constant temperature. In these situations, it is best to use the equations that involve a change in volume and pressure.
Thu Feb 06, 2020 8:23 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reversible vs irreversible work
Replies: 7
Views: 93

Re: reversible vs irreversible work

A reversible process is slow and efficient whereas an irreversible process is fast and inefficient. Also, irreversible gas expansions occur under conditions of constant external pressure while reversible gas expansions do not have constant external pressure.
Thu Jan 30, 2020 9:35 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity
Replies: 2
Views: 44

Re: Heat Capacity

It depends on what constants you are given in the problem. If you are given the molar heat capacity, you should use moles. If you are given the specific heat capacity, you should use grams.
Thu Jan 30, 2020 8:40 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Work of expansion equation
Replies: 4
Views: 48

Re: Work of expansion equation

The negative sign is there because the system loses energy by doing work of expansion. The system does work on the surroundings, and therefore it decreases in internal energy.
Wed Jan 29, 2020 2:27 pm
Forum: Calculating Work of Expansion
Topic: When to use the different work equations?
Replies: 1
Views: 20

Re: When to use the different work equations?

You would use the -P*deltaV equation when the external pressure is constant because you can pull a constant outside of the integral. However, if the external pressure is not constant, you would need to use the integral formula.
Wed Jan 29, 2020 2:25 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 3
Views: 206

Re: Sig Figs

No, if the conversion is completely equal, you do not have to consider the sig figs. So in the example you provided, 1000 ml=1 L, you would not consider those sig figs. However, a conversion factor that is not completely equal, such as molar masses, would require you to consider those sig figs.
Tue Jan 28, 2020 6:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4A7
Replies: 4
Views: 52

Re: 4A7

This constant is very commonly used because a lot of problems deal with a change in temperature of water. It can also be found on the constant and equations sheet on the class website.
Tue Jan 28, 2020 10:58 am
Forum: Phase Changes & Related Calculations
Topic: Change in Temperature
Replies: 10
Views: 64

Re: Change in Temperature

Yes, that's correct. When the temperature of a system changes, its equilibrium constant will also change.
Thu Jan 23, 2020 11:03 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Molar concentration of H3O
Replies: 6
Views: 89

Re: Molar concentration of H3O

Depending on the information given in the question, you may have to use different equations to solve for [H3O+]. An equation that relates [H3O+] to Kw would be [H3O+][OH-]=Kw.
Thu Jan 23, 2020 10:58 pm
Forum: Phase Changes & Related Calculations
Topic: Celsius and Kelvin
Replies: 11
Views: 86

Re: Celsius and Kelvin

Celsius and Kelvin will never be the same number for a given temperature. You must always convert according to the problem. The conversion is K = C+273.15, which I believe is on the equations sheet.
Thu Jan 23, 2020 10:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.35
Replies: 1
Views: 23

Re: 5.35

From the graph that is provided, you can see that A goes down 10, B goes up 5, and C goes up 10. When you simplify this ratio, there are 2 units of A, 1 unit of B, and 2 units of C. Also, A is the reactant because it decreases while B&C are the products since they increase.
Thu Jan 23, 2020 5:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Buffers
Replies: 2
Views: 28

Re: Buffers

Buffers are different because there will be initial concentrations for both the weak acid/base and its conjugate. Often times, these concentrations are the same. However, the way the ICE table is used, the techniques, and the rules for approximation are still the same.
Thu Jan 23, 2020 5:16 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: state property
Replies: 5
Views: 31

Re: state property

Other examples of state properties include energy, pressure, volume, temperature, density, and heat capacity.
Thu Jan 23, 2020 5:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: sig figs
Replies: 2
Views: 21

Re: sig figs

Yes, you should consider the sig figs for the equilibrium constants because they are calculated from concentrations that have limits on their sig figs too.
Thu Jan 16, 2020 11:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: acidity and basicity constant
Replies: 4
Views: 28

Re: acidity and basicity constant

There are different names for equilibrium constants because they provide a little bit more information about the system that is being studied. Kc means the system is dealing with concentrations, Kp means the system is dealing with partial pressures, Kw has to do with water, Ka is for weak acids, and...
Thu Jan 16, 2020 11:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Equilibrium
Replies: 9
Views: 110

Re: Solids and Equilibrium

Solids and liquids do not affect equilibrium or the equilibrium constant. Solids do not have concentration, which is why they do not affect equilibrium. Liquids are usually solvents and have insignificant changes in concentration, so they do not affect equilibrium either.
Thu Jan 16, 2020 11:21 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Stress
Replies: 4
Views: 45

Re: Stress

Different stresses that can be applied to a system at equilibrium include:
Change the pressure of the system (by manipulation volume or by adding an inert gas)
Changing the temperature of the system
Thu Jan 16, 2020 11:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tips for Test
Replies: 23
Views: 369

Re: Tips for Test

There is an announcement on the class website that says that the test is on chemical equilibrium & acid-base equilibria. I think a good way to study for the test is to do as much practice as possible to get exposed to a variety of different questions. If possible, try to do all of the problems t...
Thu Jan 16, 2020 1:51 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas and Le Chatliers
Replies: 7
Views: 81

Re: Inert Gas and Le Chatliers

Although adding an inert gas will increase the pressure of a system, the partial pressures of the reactive gases are not changing because the volume has stayed the same. Therefore, K stays the same and there is no shift in the system.
Thu Jan 16, 2020 1:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and liquids
Replies: 3
Views: 20

Re: Solids and liquids

Solids do not have concentration or pressure, which is why they are left out of K expressions.
Liquids are usually solvents and have a very insignificant change in concentration, which is why they are not included in K expressions either.
Wed Jan 08, 2020 2:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure of gas
Replies: 5
Views: 57

Re: Partial Pressure of gas

There are many units for pressure, and you should use the unit that is presented in the problem if possible. Otherwise, common units for pressure are: atmospheres (atm), torr, bar, and pascals (Pa). There may be more, but these are the common ones I think.
Wed Jan 08, 2020 2:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure vs. Concentration
Replies: 4
Views: 34

Re: Partial Pressure vs. Concentration

Kp can only be used for gases because only gases can exert pressure on a container. Therefore, if you only have aqueous solutions in your chemical equation, then you know you must calculate for Kc since there are no gases. If you have only gases in your chemical equation, you can solve for either Kc...
Wed Jan 08, 2020 1:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solvents
Replies: 5
Views: 56

Re: Solvents

Solvents are not included in the equilibrium constant equation because the concentration of a solvent does not change significantly in equilibrium reactions. There is such a large excess of solvent in these reactions that their concentration is essentially constant throughout the reaction.
Wed Jan 08, 2020 12:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Increasing the concentration of products?
Replies: 3
Views: 27

Re: Increasing the concentration of products?

When the concentration of the products is increased in an equilibrium reaction, the reverse reaction will be favored and more reactants will be formed.
Wed Jan 08, 2020 11:58 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Comparing Q and K
Replies: 3
Views: 39

Re: Comparing Q and K

When Q<K, the reaction will proceed in the forward direction and favor the products.
When Q>K, the reaction will proceed in the reverse direction and favor the reactants.
Wed Jan 08, 2020 10:20 am
Forum: Ideal Gases
Topic: Equilibrium
Replies: 7
Views: 89

Re: Equilibrium

Q and K are calculated in the same way by using the same equation. However, K is a constant that is calculated using the concentrations when the reaction reaches equilibrium while Q changes as the reaction proceeds. Often, we compare Q and K to determine which direction the reaction will continue ov...
Wed Dec 04, 2019 10:10 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Melting point of solid argon vs. xenon
Replies: 2
Views: 39

Re: Melting point of solid argon vs. xenon

Argon and Xenon are both nonpolar. Therefore, the only forces that they experience are induced-dipole induced-dipole forces. Since Xenon is a larger atom than Argon and has more electrons, these induced-dipole induced-dipole forces are stronger in Xenon than in Argon. Therefore, it would take more e...
Wed Dec 04, 2019 9:56 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C19 parts b and e
Replies: 1
Views: 31

Re: 6C19 parts b and e

The fact that there are more oxygen atoms is an explanation for anion stability. Since there are more oxygens, there is more electron-pulling power in the anion that will delocalize the charge more, making the anion more stable.
Wed Dec 04, 2019 9:47 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Oxoacids
Replies: 2
Views: 44

Re: Oxoacids

An oxoacid is an acid that contains one or more oxygen atoms. Generally, an oxoacid contains hydrogen, oxygen, and at least one other element. For example, H3PO4 and HNO3 are both oxoacids.
Wed Dec 04, 2019 9:43 am
Forum: Bronsted Acids & Bases
Topic: Bronsted Acids/Bases in Equations
Replies: 5
Views: 116

Re: Bronsted Acids/Bases in Equations

Generally in a chemical equation, the Bronsted acid and base are both reactants. When they react, the products are a conjugate base and a conjugate acid.
Wed Dec 04, 2019 9:34 am
Forum: Naming
Topic: 9C 1 part a
Replies: 2
Views: 67

Re: 9C 1 part a

When naming the ligands in a coordination compound, the -ide suffix is dropped and is replaced with -o.
Since CN- is cyanide, the -ide is dropped and replaced with -o when used in naming for a coordination compound, and it becomes cyano.
Wed Dec 04, 2019 9:29 am
Forum: Hybridization
Topic: Terminal Atoms
Replies: 2
Views: 53

Re: Terminal Atoms

Terminal atoms are the other atoms in a molecule that are not the central atom. For example, in methane (CH 4 ), the carbon atom would be the central atom and the four hydrogens are all terminal atoms. For the final, I guess you should know what it means, but it is something that shouldn't be too ha...
Mon Nov 25, 2019 5:44 pm
Forum: Naming
Topic: -ide naming
Replies: 1
Views: 32

Re: -ide naming

No, actually the -ide suffix means that they are ions. So chloride would be Cl- and bromide would be Br-.
Mon Nov 25, 2019 11:16 am
Forum: Bronsted Acids & Bases
Topic: Bronsted vs Lewis Acid/Base
Replies: 5
Views: 44

Re: Bronsted vs Lewis Acid/Base

Bronsted and Lewis acids/bases are just two different ways to define acids/bases. Neither is more correct, and there is no difference in the actual compounds. The Bronsted definition is based on the donation/reception of protons. The Lewis definition is based on the donation/reception of lone pairs ...
Mon Nov 25, 2019 9:35 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Inter-ionic forces
Replies: 3
Views: 45

Re: Inter-ionic forces

The electrostatic attraction between a cation and an anion is depended on the charges of the ions as well as the distance between them. The force is stronger if the charges of the ions are higher. In other words, the strength of the force is directly proportional to the charges of the ions. The forc...
Mon Nov 25, 2019 9:30 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination compound
Replies: 5
Views: 60

Re: Coordination compound

I don't believe there is any difference between these terms. They are all different, interchangeable ways to identify the compounds we have been discussing in lecture.
Mon Nov 25, 2019 9:28 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: ligand bonding sites
Replies: 2
Views: 68

Re: ligand bonding sites

When a ligand binds at multiple sites, it means that one single ligand donates multiple electron pairs to the transition metal cation and binds to it in multiple locations.
Mon Nov 25, 2019 9:24 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Inorganic vs Organic Acids
Replies: 3
Views: 76

Re: Inorganic vs Organic Acids

The acids found in biological systems tend to be weaker because many biological processes tend to be pH-dependent. A strong acid will decrease the pH of a system much more than a weak acid will. Therefore, organic acids tend to be weaker because they will not as drastically change the pH of a biolog...
Wed Nov 20, 2019 10:45 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Polar/nonpolar boiling point
Replies: 2
Views: 38

Re: Polar/nonpolar boiling point

Polar molecules tend to have higher boiling points than nonpolar molecules because of the presence of dipole-dipole interactions and potentially hydrogen bonding. Both of these forces are stronger than the induced dipole-induced dipole forces that are the only intermolecular forces in nonpolar molec...
Wed Nov 20, 2019 10:25 am
Forum: Hybridization
Topic: lone pairs in hybridization
Replies: 8
Views: 104

Re: lone pairs in hybridization

Lone pairs on an atom are considered regions of electron density. Therefore, they are including in the hybridization of that atom.
Wed Nov 20, 2019 10:24 am
Forum: Hybridization
Topic: hybridizing f-orbitals
Replies: 1
Views: 21

Re: hybridizing f-orbitals

In order for an f-orbital to be hybridized, there would have to be 10 regions of electron density around an atom (1 s-orbital, 3 p-orbitals, 5-d orbitals, and 1-f-orbital). I'm not sure if this possible, but it seems very unlikely. I don't think we will need to know about it for future assessments.
Wed Nov 20, 2019 10:16 am
Forum: Hybridization
Topic: pi bond orientation
Replies: 4
Views: 56

Re: pi bond orientation

Pi bonds inhibit rotation in a molecule because the orbitals that are interacting to form the bond are arranged side-by-side, not end-to-end. Since they are arranged side-by-side, rotating the molecule would prevent the orbitals from overlapping, break the pi bond, and would require a chemical react...
Wed Nov 20, 2019 9:55 am
Forum: Hybridization
Topic: Ring Structure
Replies: 2
Views: 58

Re: Ring Structure

When molecules are drawn using a ring structure, assume that all of the atoms have an octet (except for hydrogens). However, the lone pairs are often omitted in the drawing but are implied to be there. Since the lone pairs are still there, they are included in the hybridization.
Wed Nov 20, 2019 9:52 am
Forum: Hybridization
Topic: hybridizing oxygen
Replies: 5
Views: 128

Re: hybridizing oxygen

Since the oxygen has one double bond and two lone pairs, there are a total of three regions of electron density around it. Three regions of electron density correspond with an sp2 hybridization for the oxygen.
Wed Nov 13, 2019 10:17 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Ion-Ion
Replies: 2
Views: 36

Re: Ion-Ion

Yes, I believe the two are the same thing. It is just the electrostatic attraction between a positively-charged cation and a negatively-charged anion.
Wed Nov 13, 2019 10:14 am
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: 3
Views: 29

Re: hydrogen bonding

Hydrogen can only form one bond in a molecule. So in order for hydrogen bonding to take place, H has to be bonded to N, O, or F, since those atoms would create the largest electronegativity differences.
Wed Nov 13, 2019 9:36 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Intermolecular Forces vs. Chemical Bonds
Replies: 3
Views: 59

Re: Intermolecular Forces vs. Chemical Bonds

Intermolecular forces occur between separate molecules while chemical bonds occur within one single molecule.
Wed Nov 13, 2019 9:27 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Molecule Size and Melting Points
Replies: 6
Views: 79

Re: Molecule Size and Melting Points

Bigger molecules have larger electron clouds, which make them more polarizable. This will lead to stronger dipole moments between the molecules and stronger attractive forces. This will increase the melting and boiling points of the compounds.
Wed Nov 13, 2019 9:21 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London Forces and Dipole-Dipole
Replies: 5
Views: 116

Re: London Forces and Dipole-Dipole

London dispersion forces act on all atoms and molecules. This includes polar molecules and nonpolar molecules.
Wed Nov 13, 2019 9:12 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Single/Double Bonds in Resonance
Replies: 6
Views: 77

Re: Single/Double Bonds in Resonance

I don't believe resonance structures really impact the VSEPR model. The model only depends on the number of atoms bonded to the central atom and the number of lone pairs on the central atom. Whether or not there is resonance, single bonds, or double bonds, it does not affect a molecule's shape accor...
Wed Nov 06, 2019 1:12 pm
Forum: Einstein Equation
Topic: Einstein Equation
Replies: 10
Views: 223

Re: Einstein Equation

The h stands for Planck's constant, which is provided on the constants sheet.
The v stands for the frequency of EM radiation that is being used in the calculation.
Wed Nov 06, 2019 10:46 am
Forum: Dipole Moments
Topic: Drawing Unpaired Electrons
Replies: 7
Views: 90

Re: Drawing Unpaired Electrons

You should always account for all of the electrons in the Lewis structure. They could be as lone pairs or in bonds, but all of the electrons should be represented in the structure.
Wed Nov 06, 2019 9:49 am
Forum: Octet Exceptions
Topic: octet exceptions
Replies: 3
Views: 66

Re: octet exceptions

There are other exceptions that can have expanded octets beyond just P, S, and Cl. Any element that would have unfilled d-orbitals able to be used would be able to accommodate extra electrons and have an expanded octet. It's just that the first ones that are able to do this are P, S, and Cl.
Mon Nov 04, 2019 9:48 am
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent bonds
Replies: 1
Views: 42

Re: Ionic and Covalent bonds

Metals tend to have lower electronegativity values while nonmetals tend to have higher electronegativity values. Since the difference in electronegativity between a metal and a nonmetal is typically large, they form ionic bonds. Similarly, since the difference in electronegativity between two nonmet...
Mon Nov 04, 2019 9:41 am
Forum: Ionic & Covalent Bonds
Topic: Ionic and covalent bonds
Replies: 2
Views: 51

Re: Ionic and covalent bonds

Covalent compounds are drawn using lines, which represent the sharing of electrons (covalent bonds).
Ionic compounds are drawn as separate ions that are close to one another because of their electrostatic attraction.
Mon Nov 04, 2019 9:27 am
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 2
Views: 68

Re: Octet Exceptions

Elements that do not require an octet include:

The first four elements (H, He, Li, Be)
Boron (B), Aluminum (Al), and the rest of that group. These elements sometimes have only 6 valence electrons rather than a full octet.
Tue Oct 29, 2019 7:37 pm
Forum: Lewis Structures
Topic: If the overall charge of a Lewis Structure is -1, does that mean all the atoms' charges are adding to -1?
Replies: 4
Views: 52

Re: If the overall charge of a Lewis Structure is -1, does that mean all the atoms' charges are adding to -1?

Yes, if you are drawing a Lewis structure for an ion, the sum of all of the formal charges in the ion must equal the total charge of the ion.
Tue Oct 29, 2019 7:33 pm
Forum: Ionic & Covalent Bonds
Topic: Strength of ionic and covalent bonds
Replies: 2
Views: 27

Re: Strength of ionic and covalent bonds

Ionic bonds are typically stronger than covalent bonds since they involve two particles that have full positive/negative charges rather than just the sharing of electrons. Double bonds are stronger than single bonds because there are more electrons involved in the sharing. In addition, double bonds ...
Tue Oct 29, 2019 11:37 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Equation
Replies: 2
Views: 53

Re: Formal Charge Equation

The formal charge equation that Professor Lavelle provided in class is a little confusing to understand, but it is just the # of valence electrons of the atom minus the number of lone pair electrons minus half the number of bonding electrons: FC = V - (L +.5B) So for example, if you have a Lewis str...
Mon Oct 28, 2019 7:40 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration exceptions
Replies: 2
Views: 64

Re: Electron configuration exceptions

Yes, I believe that those elements also follow the same pattern that chromium and copper have.
Mon Oct 28, 2019 10:39 am
Forum: Lewis Structures
Topic: Central Atoms
Replies: 2
Views: 39

Re: Central Atoms

The central atom of a molecule is most typically an atom of the element with the lowest ionization energy. However, hydrogen is never central as it can only form one bond.

Therefore, for NHF2, the central atom would be nitrogen as it has the lowest ionization energy and is not hydrogen.
Mon Oct 28, 2019 10:37 am
Forum: Resonance Structures
Topic: Resonance Clarification
Replies: 8
Views: 110

Re: Resonance Clarification

When a molecule has resonance, it means that a multiple bond (double bond, triple bond, etc.) can be placed in different locations within the molecule without having to move the individual atoms in the structure.
Sun Oct 27, 2019 5:45 pm
Forum: Trends in The Periodic Table
Topic: Central Atom
Replies: 13
Views: 155

Re: Central Atom

The central atom of a molecule is usually an atom of the element with the lowest ionization energy.
Sat Oct 26, 2019 1:21 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: ml alue (i.e., ...-1,0,1,....)
Replies: 2
Views: 52

Re: ml alue (i.e., ...-1,0,1,....)

Once you've determined the l value, you can determine the possible ml values. The values ml can have are -l, -l+1, ..., 0, ..., l-1, l.
In simpler terms, the possible values of ml are the whole number values between -l and l.
For example, if l=2, ml can be -2, -1, 0, 1, 2.
Sat Oct 26, 2019 1:14 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Formal Charge
Replies: 3
Views: 40

Re: Formal Charge

Yes, you should aim for formal charges of 0 because that will give you the most accurate Lewis structure for the molecule you are modeling. However, achieving formal charges for every atom in the molecule may not be possible.
Sat Oct 26, 2019 12:53 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1D. 13
Replies: 1
Views: 40

Re: 1D. 13

For an electron in the 3p subshell:
n=3 (3rd principal energy level)
l=1 (p subshell)

Since ml can have values of -l, -l+1,..., l-1, l, the only possible values of ml would be -1,0,1.