Search found 23 matches

by 204932558
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: 278

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

log and ln are not the same. Ln(x) = 2.303log(x)
by 204932558
Fri Mar 16, 2018 8:03 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: State functions?
Replies: 9
Views: 324

Re: State functions?

They are both state functions. Gibbs free energy is another example.
by 204932558
Wed Mar 14, 2018 10:38 am
Forum: Balancing Redox Reactions
Topic: Half-reactions
Replies: 4
Views: 139

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.
by 204932558
Sat Mar 03, 2018 8:51 pm
Forum: Zero Order Reactions
Topic: slope
Replies: 9
Views: 255

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.
by 204932558
Sat Mar 03, 2018 8:33 pm
Forum: First Order Reactions
Topic: Terminology "first-order" [ENDORSED]
Replies: 5
Views: 158

Re: Terminology "first-order" [ENDORSED]

The overall order of a reaction is the sum of the order of reactions for each reactants.
by 204932558
Sat Mar 03, 2018 8:29 pm
Forum: First Order Reactions
Topic: Deriving these Equations
Replies: 7
Views: 189

Re: Deriving these Equations

[A}0 means the initial concentration. [A} is the concentration at any given time.
by 204932558
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: 170

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.
by 204932558
Sat Feb 24, 2018 10:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: reducing power?
Replies: 5
Views: 140

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.
by 204932558
Sat Feb 24, 2018 10:31 pm
Forum: Balancing Redox Reactions
Topic: Basic and Acidic conditions [ENDORSED]
Replies: 11
Views: 3168

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.
by 204932558
Sat Feb 17, 2018 11:58 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Diagram
Replies: 3
Views: 374

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.
by 204932558
Sat Feb 17, 2018 11:54 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Standard Cell Potential
Replies: 4
Views: 380

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.
by 204932558
Sat Feb 17, 2018 11:17 pm
Forum: Calculating Work of Expansion
Topic: Isolated System
Replies: 5
Views: 195

Re: Isolated System

Yes, as no heat or matter flows into the system or exits the system.
by 204932558
Sat Feb 10, 2018 9:44 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 8.31
Replies: 7
Views: 254

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.
by 204932558
Sat Feb 10, 2018 9:40 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Question 9.21
Replies: 4
Views: 138

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).
by 204932558
Sat Feb 10, 2018 9:30 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9. 43
Replies: 5
Views: 159

Re: 9. 43

The value is fixed and given, so you don't have to calculate it.
by 204932558
Sat Feb 03, 2018 12:25 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Exergonic [ENDORSED]
Replies: 5
Views: 122

Re: Exergonic [ENDORSED]

Cellular respiration is an exergonic process. ATP is broken down to ADP and Pi during hydrolysis and energy is released.
by 204932558
Sat Feb 03, 2018 10:13 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Gas Expansion [ENDORSED]
Replies: 3
Views: 169

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.
by 204932558
Sat Feb 03, 2018 9:48 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: bond enthalpy [ENDORSED]
Replies: 4
Views: 139

Re: bond enthalpy [ENDORSED]

I think generally, there is a positive correlation between polarity and bond enthalpy but the there can be exceptions.
by 204932558
Sat Jan 27, 2018 12:09 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Examples of work being done
Replies: 7
Views: 225

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.
by 204932558
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: 196

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.
by 204932558
Tue Jan 23, 2018 10:43 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: mass in q = m(c) delta t
Replies: 5
Views: 346

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

Molar heat capacity uses J/Kg.M as the unit.
by 204932558
Sun Jan 14, 2018 2:40 pm
Forum: Phase Changes & Related Calculations
Topic: Endo and Exothermic Ways to Remember
Replies: 28
Views: 1711

Re: Endo and Exothermic Ways to Remember

"En" kinda sounds like "in" and "ex" means "exit".
by 204932558
Sun Jan 14, 2018 2:31 pm
Forum: Phase Changes & Related Calculations
Topic: Why can state properties be added?
Replies: 11
Views: 363

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.

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