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: 451
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: 496
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: 799
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: 638
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: 1924
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: 998
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: 637
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: 655
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: 724
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
- Topic: Adiabatic vs. Isochoric
- Replies: 2
- Views: 550
Adiabatic vs. Isochoric
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: 260
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: 724
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: 724
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: 2145
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: 1164
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: 486
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: 334
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: 486
Test 2
Will we be expected to know how to calculate the standard potential of a couple
from two related couples on test 2?
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: 975
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: 492
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: 436
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.
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: 506
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: 2755
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: 372
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: 402
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: 918
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: 299
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: 2027
Re: Examples of Open Closed Isolated
open: bowl of hot soup
closed: a sealed bag of fruit
isolated: an insulated coffee mug
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: 2442
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: 1790
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: 1016
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: 861
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: 942
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: 222
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: 309
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: 258
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: 54
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: 237
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: 193
Re: HW Q
You should repeat the same process of finding pH, but instead use the actual volume used, which was 250 mL.