Search found 39 matches

Sat Mar 16, 2019 10:18 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Reduction Potentials
Replies: 2
Views: 260

Re: Reduction Potentials

I find it much simpler to do Ecathode-Eanode instead of reversing cell potentials.
Sat Mar 16, 2019 10:17 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell potential and Gibbs Free energy
Replies: 2
Views: 287

Re: Cell potential and Gibbs Free energy

You can find n easily after balancing the redox reaction.
Sat Mar 16, 2019 10:16 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Determining n
Replies: 6
Views: 423

Re: Determining n

N is 2 because 1 electron is being added to Ce, but there are two moles of it so you multiply the number of electrons added/removed by the number of moles of the reduced/oxidized compound.
Sat Mar 16, 2019 10:14 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: cell potential
Replies: 3
Views: 321

Re: cell potential

I find it more straightforward to do Ecathode- Eanode rather than reversing Ecell because sometimes the reduction potential is negative and it can get confusing.
Sat Mar 16, 2019 10:12 pm
Forum: Phase Changes & Related Calculations
Topic: Specific heat capacity of ice
Replies: 2
Views: 1658

Re: Specific heat capacity of ice

Since each of them have their own phase change, you use that phase's specific heat capacity.
Sat Mar 16, 2019 10:11 pm
Forum: Van't Hoff Equation
Topic: neutral pH not 7?
Replies: 6
Views: 499

Re: neutral pH not 7?

Using the vant hoff equation can help you see how temperature affects K. From there you can determine if a certain pH is neutral.
Sat Mar 16, 2019 10:08 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 3
Views: 361

Re: Arrhenius Equation

To add, using the arrhenius equation to solve for pre-exponential factor, A, gives you insight into the frequency of collisions that are in the correct orientation.
Sat Mar 16, 2019 10:07 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 4
Views: 336

Re: Catalysts

You should also know that a catalyst doesn't appear in the overall reaction.
Sat Mar 16, 2019 10:06 pm
Forum: *Enzyme Kinetics
Topic: Collision theory
Replies: 3
Views: 385

Re: Collision theory

You can tell if a reaction is likely to occur through the sign of delta G or Epotential.
Wed Mar 13, 2019 11:49 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Replies: 2
Views: 307

What is the difference between adiabatic and isochoric?
Sun Mar 10, 2019 11:01 pm
Forum: First Order Reactions
Topic: Pseudo rate laws
Replies: 2
Views: 101

Re: Pseudo rate laws

When you have a reaction that is not first order and you want to determine one of the reactant's concentration, you can use a pseudo-first-order reaction in which one of the reactants is in great excess, essentially remaining constant as the reaction progresses. This allows you to determine concentr...
Sun Mar 10, 2019 10:57 pm
Forum: First Order Reactions
Topic: Half-Life
Replies: 7
Views: 243

Re: Half-Life

To add, half-life is important to determine how quickly quickly unstable atoms undergo, or how long stable atoms survive, radioactive decay.
Sun Mar 10, 2019 10:56 pm
Forum: First Order Reactions
Topic: Half-Life
Replies: 7
Views: 243

Re: Half-Life

Half life is the time that it takes for a substance to decompose into half of its intial state, no matter the state.
Sun Mar 10, 2019 10:54 pm
Forum: Zero Order Reactions
Topic: Graphs
Replies: 8
Views: 624

Re: Graphs

I think that you should always get a linear plot for 0,1,and 2 order reactions!
Sun Mar 03, 2019 9:10 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Porous Disk and Salt Bridge
Replies: 13
Views: 482

Re: Porous Disk and Salt Bridge

I don't believe that one is more efficient than the other.
Sun Mar 03, 2019 8:59 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2
Replies: 4
Views: 237

Re: Test 2

Thank you!
Sun Mar 03, 2019 8:58 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Q
Replies: 3
Views: 139

Re: Q

You should usually stick to using either concentration or partial pressures when calculating Q
Sun Feb 24, 2019 1:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2
Replies: 4
Views: 237

Test 2

Will we be expected to know how to calculate the standard potential of a couple
from two related couples on test 2?
Fri Feb 22, 2019 11:14 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: units
Replies: 7
Views: 468

Re: units

Pressure can sometimes be given in Pascals or kilopascals as well.
Fri Feb 22, 2019 10:38 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Relationship between K and G
Replies: 3
Views: 205

Re: Relationship between K and G

It helps to think of this in terms of k in an equilibrium equation to determine whether it will proceed to reactants vs products.
Fri Feb 22, 2019 10:34 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs Free Energy
Replies: 4
Views: 138

Re: Gibbs Free Energy

When deltaG is positive the reactants are more thermodynamically stable, so the reaction proceeds to the left.
When deltaG is negative the products are more thermodynamically stable, so the reaction proceeds to the right.
Mon Feb 18, 2019 4:57 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: standard Gibbs Free Energy
Replies: 4
Views: 149

Re: standard Gibbs Free Energy

Using "standard" simply indicates that the substances in question are in standard state.
Mon Feb 18, 2019 4:56 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G a state function?
Replies: 23
Views: 852

Re: Delta G a state function?

Yes, free energy is a state function
Mon Feb 18, 2019 4:55 pm
Forum: Van't Hoff Equation
Topic: Different Constants of Eqn
Replies: 3
Views: 160

Re: Different Constants of Eqn

To add, when the equation is derived, delta g is assumed to be zero since the system is at equilibrium
Sun Feb 10, 2019 12:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H
Replies: 4
Views: 177

Re: Delta H

To add, delta H can also equal w if the temperature of the system is not changing because delta h = q+w and q would then be zero.
Sun Feb 10, 2019 12:50 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: methods
Replies: 8
Views: 338

Re: methods

You can also cross out bonds if both the products and reactants both have the same number!
Sun Feb 10, 2019 12:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Using Bond Enthalpies
Replies: 2
Views: 118

Using Bond Enthalpies

When a structure has resonance and you are calculating the enthalpy for its formation, how do you know whether to use the bond formation enthalpy for its single, double, or triple bonds?
Mon Feb 04, 2019 12:11 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Examples of Open Closed Isolated
Replies: 5
Views: 179

Re: Examples of Open Closed Isolated

open: bowl of hot soup
closed: a sealed bag of fruit
isolated: an insulated coffee mug
Mon Feb 04, 2019 12:08 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Cup of Tea
Replies: 17
Views: 756

Re: Cup of Tea

since in a cup of tea will cool down over time, it will exchange energy with surroundings. since a cup is typically not covered on the top, tea could also leave the system . since both matter and energy can be exhanged, then a cup of tea is an open system
Mon Feb 04, 2019 12:06 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated System (Water bottle)
Replies: 6
Views: 386

Re: Isolated System (Water bottle)

an insulated water bottle would keep temperature (energy) constant and if it is closed then no water will leave. this means that no matter or energy is exchanged, the qualifications for an isolated system
Sun Jan 27, 2019 3:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH
Replies: 9
Views: 437

Re: pH

pH is a measure of the amount of free hydrogen and hydroxyl ions in the water. Water that has more H+ ions is acidic, but water that has more OH- ions is basic. pH is affected by chemicals in the water, so it can be indicative of chemical changes happening in water.
Sun Jan 27, 2019 3:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What not to count
Replies: 9
Views: 361

Re: What not to count

You can typically disregard elements that don't affect the pH/pOH.
Sun Jan 27, 2019 3:48 pm
Forum: Phase Changes & Related Calculations
Topic: Why are phase changes endothermic?
Replies: 11
Views: 403

Re: Why are phase changes endothermic?

Phase changes like freezing, however release energy into the surroundings so it can be considered exothermic.
Sun Jan 20, 2019 10:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.3 6th edition
Replies: 3
Views: 114

Re: 11.3 6th edition

I think the directions should tell you to balance it first.
Sun Jan 20, 2019 5:14 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Salt formation
Replies: 3
Views: 133

Salt formation

How is a salt formed?
Sun Jan 20, 2019 5:01 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength and Weakness
Replies: 2
Views: 110

Re: Strength and Weakness

You can compare the strength of two acids by comparing their acidity constants. small Ka values correspond to weak acids.
Sun Jan 20, 2019 3:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: reaction of AlCl3
Replies: 1
Views: 34

Re: reaction of AlCl3

AlCl3 can act as an acid because it accepts electrons.
Sun Jan 20, 2019 3:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Assuming X value
Replies: 3
Views: 107

Re: Assuming X value

You can typically assume that the value of x is negligible when the Ka or Kb is less that 10^-3. If it's not, then you should always include x in your calculations.
Sun Jan 20, 2019 3:25 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: HW Q
Replies: 2
Views: 72

Re: HW Q

You should repeat the same process of finding pH, but instead use the actual volume used, which was 250 mL.