## Search found 23 matches

Fri Mar 16, 2018 8:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equations: ln Q vs. log Q [ENDORSED]
Replies: 5
Views: 690

### Re: Equations: ln Q vs. log Q[ENDORSED]

log and ln are not the same. Ln(x) = 2.303log(x)
Fri Mar 16, 2018 8:03 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: State functions?
Replies: 9
Views: 642

### Re: State functions?

They are both state functions. Gibbs free energy is another example.
Wed Mar 14, 2018 10:38 am
Forum: Balancing Redox Reactions
Topic: Half-reactions
Replies: 4
Views: 308

### Re: Half-reactions

Yes. Just make sure the electrons cancel out, and that the reaction with a more negative reduction potential is one being flipped.
Sat Mar 03, 2018 8:51 pm
Forum: Zero Order Reactions
Topic: slope
Replies: 9
Views: 1375

### Re: slope

The graph for zero order reaction and first order reaction is {A} against time. But for second order reaction it's 1/[A] against time, which is why the slope is negative.
Sat Mar 03, 2018 8:33 pm
Forum: First Order Reactions
Topic: Terminology "first-order" [ENDORSED]
Replies: 5
Views: 318

### Re: Terminology "first-order"[ENDORSED]

The overall order of a reaction is the sum of the order of reactions for each reactants.
Sat Mar 03, 2018 8:29 pm
Forum: First Order Reactions
Topic: Deriving these Equations
Replies: 7
Views: 428

### Re: Deriving these Equations

[A}0 means the initial concentration. [A} is the concentration at any given time.
Sat Feb 24, 2018 11:09 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.31
Replies: 6
Views: 392

### Re: 14.31

If Ecell is positive, G is negative according to G=-nEf. It means the forward reaction is spontaneous and therefore favored, resulting in a K greater than 1.
Sat Feb 24, 2018 10:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: reducing power?
Replies: 5
Views: 882

### Re: reducing power?

Reducing power of a species is the ability to reduce other another species. The higher the reducing power, the lower the reduction potential, and the less likely the species itself becomes reduced.
Sat Feb 24, 2018 10:31 pm
Forum: Balancing Redox Reactions
Topic: Basic and Acidic conditions [ENDORSED]
Replies: 11
Views: 3656

### Re: Basic and Acidic conditions[ENDORSED]

Yes. OH- is used in basic environment and H+ is used in acidic environment. H20 is added after the the addition of H+ and OH-, balancing the whole equation.
Sat Feb 17, 2018 11:58 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Diagram
Replies: 3
Views: 617

### Re: Cell Diagram

Because silver loses an electron and becomes oxidized and bromine gains an electron and becomes reduced. They both need to be included in the cell expression.
Sat Feb 17, 2018 11:54 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Standard Cell Potential
Replies: 4
Views: 569

### Re: Standard Cell Potential

It' s zero because we use the reaction of hydrogen as a reference to calculate the potential of other redox reactions.
Sat Feb 17, 2018 11:17 pm
Forum: Calculating Work of Expansion
Topic: Isolated System
Replies: 5
Views: 382

### Re: Isolated System

Yes, as no heat or matter flows into the system or exits the system.
Sat Feb 10, 2018 9:44 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 8.31
Replies: 7
Views: 501

### Re: Question 8.31

Kelvin = 273 + Degree Celcius. So it doesn't matter if you use either since the temperature difference is the same for both units.
Sat Feb 10, 2018 9:40 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Question 9.21
Replies: 4
Views: 245

### Re: Question 9.21

For the first part, the degeneracy is 1^64, so S = ln(1^64) = 0. For the second part, S = ln(4^64).
Sat Feb 10, 2018 9:30 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9. 43
Replies: 5
Views: 347

### Re: 9. 43

The value is fixed and given, so you don't have to calculate it.
Sat Feb 03, 2018 12:25 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Exergonic [ENDORSED]
Replies: 5
Views: 266

### Re: Exergonic[ENDORSED]

Cellular respiration is an exergonic process. ATP is broken down to ADP and Pi during hydrolysis and energy is released.
Sat Feb 03, 2018 10:13 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Gas Expansion [ENDORSED]
Replies: 3
Views: 272

### Re: Gas Expansion[ENDORSED]

DeltaU = deltaQ + work. When the gas expands, it does work to the surrounding. But that loss of internal energy can be made up by the heat flowing into the system. So overall, U can stay unchanged.
Sat Feb 03, 2018 9:48 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: bond enthalpy [ENDORSED]
Replies: 4
Views: 293

### Re: bond enthalpy[ENDORSED]

I think generally, there is a positive correlation between polarity and bond enthalpy but the there can be exceptions.
Sat Jan 27, 2018 12:09 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Examples of work being done
Replies: 7
Views: 519

### Re: Examples of work being done

If gas expands against vacuum no work is being done because the external pressure is zero. An example of work done on a system would be a piston compressing the gas inside a column. Work is done on the gas.
Fri Jan 26, 2018 2:32 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 5
Views: 372

### Re: Bond Enthalpies

Bond enthalpy is an average value of the energies required to break/form a certain type of bond in MANY MOLECULES. Therefore each molecule's bond enthalpy differs.
Tue Jan 23, 2018 10:43 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: mass in q = m(c) delta t
Replies: 5
Views: 542

### Re: mass in q = m(c) delta t

Molar heat capacity uses J/Kg.M as the unit.
Sun Jan 14, 2018 2:40 pm
Forum: Phase Changes & Related Calculations
Topic: Endo and Exothermic Ways to Remember
Replies: 28
Views: 5796

### Re: Endo and Exothermic Ways to Remember

"En" kinda sounds like "in" and "ex" means "exit".
Sun Jan 14, 2018 2:31 pm
Forum: Phase Changes & Related Calculations
Topic: Why can state properties be added?
Replies: 11
Views: 708

### Re: Why can state properties be added?

Being a state property means its value is always the same under certain conditions, no matter how the value is obtained.