Search found 22 matches

by Melodie Oh 2A
Sat Mar 17, 2018 10:30 pm
Forum: General Rate Laws
Topic: 15.35
Replies: 1
Views: 283

Re: 15.35

It's because the [A]=1/60[A0] meaning that 1/[A] would be 1/1/60[A0] which becomes 16/[A0]
by Melodie Oh 2A
Sat Mar 17, 2018 10:28 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Catalyst and Intermediate
Replies: 7
Views: 409

Catalyst and Intermediate

How do you know the difference between a catalyst and in intermediate in a reaction mechanism??
by Melodie Oh 2A
Sat Mar 17, 2018 10:26 pm
Forum: *Alkanes
Topic: The symbol R
Replies: 4
Views: 447

Re: The symbol R

Sometimes it can also include halogen, nitrogen or oxygen.
by Melodie Oh 2A
Sat Mar 17, 2018 7:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Elementary Reaction
Replies: 2
Views: 218

Elementary Reaction

How do you know when an elementary reaction is slow or fast?
by Melodie Oh 2A
Mon Feb 19, 2018 5:46 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Example 14.4
Replies: 1
Views: 56

Example 14.4

For the reaction of Pt(s)|H2(g)|HCl(aq)|Hg2Cl2(s)|Hg(l), it becomes Hg2Cl(s) + H2(g) --> 2Hg(l) + 2Cl-(aq) + 2H+(aq).

What does the Pt stand for and why isn't it included in the reaction equation?
by Melodie Oh 2A
Tue Feb 13, 2018 9:06 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Heat and Enthalpy
Replies: 1
Views: 136

Heat and Enthalpy

What exactly is the difference between heat and enthalpy??
by Melodie Oh 2A
Tue Feb 13, 2018 1:22 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: 9.25 Question
Replies: 1
Views: 111

9.25 Question

How can there be 6 orientations for the molecule SO2F02?
by Melodie Oh 2A
Fri Feb 09, 2018 12:19 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Pressure and Volume
Replies: 3
Views: 92

Re: Pressure and Volume

Because the units cancel out in the ratio, the unit doesn't really matter. You just have to make sure that the units of the two volume or pressure are the same.
by Melodie Oh 2A
Thu Feb 08, 2018 3:19 pm
Forum: Van't Hoff Equation
Topic: Exothermic and decrease in tempterature
Replies: 4
Views: 287

Re: Exothermic and decrease in tempterature

Whenever a temperature is lowered, the exothermic process is favored so yes, the formation of the product will be favored. I would say that the favorability of the product or reactant when the temperature changes depend on what type of a reaction it is (endothermic or exothermic).
by Melodie Oh 2A
Thu Feb 08, 2018 3:16 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Clausius inequality
Replies: 1
Views: 85

Clausius inequality

I was reading the textbook and I wasn't too sure on the concept of Clausius inequality. How exactly does deltaS >q/T work if the equation that are given to us are deltaS=q/T?
by Melodie Oh 2A
Thu Feb 01, 2018 5:11 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Change of Entropy for V and T
Replies: 2
Views: 115

Change of Entropy for V and T

Why does the equation of entropy change for change in volume use V2/V1 while it is P1/P2 for the change in pressure?
by Melodie Oh 2A
Thu Feb 01, 2018 5:09 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: units conversion for entropy
Replies: 6
Views: 197

Re: units conversion for entropy

It doesn't really matter but usually entropy is in J/K due to the equation of S=q/T
by Melodie Oh 2A
Mon Jan 29, 2018 5:37 pm
Forum: Calculating Work of Expansion
Topic: Reversible vs Irreversible
Replies: 4
Views: 198

Reversible vs Irreversible

I read the textbook and I still don't really understand the concept of reversible and irreversible expansion. What exactly are the difference between the two in terms of the work??
by Melodie Oh 2A
Thu Jan 25, 2018 3:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 5
Views: 234

Re: Bond Enthalpies

This is because bond enthalpies uses the average bond, and doesn't take the intermolecular forces into account.
by Melodie Oh 2A
Thu Jan 25, 2018 3:54 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calculating heat (q)
Replies: 4
Views: 318

Re: Calculating heat (q)

This will depend on the c value that you have. If you have the molar heat capacity and the second equation will be used and if you have the specific heat capacity the first one will be used.
by Melodie Oh 2A
Thu Jan 25, 2018 3:49 pm
Forum: Phase Changes & Related Calculations
Topic: enthalpy of fusion/vaporization
Replies: 3
Views: 130

Re: enthalpy of fusion/vaporization

You basically take the negative of the enthalpy of fusion/vaporization if the process is in reverse.
by Melodie Oh 2A
Thu Jan 18, 2018 9:55 pm
Forum: Calculating Work of Expansion
Topic: Work for compression/expansion
Replies: 2
Views: 103

Work for compression/expansion

Can someone explain why the value for work is positive when it is compression and why it is negative when it is expansion??
by Melodie Oh 2A
Thu Jan 18, 2018 9:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Is there a way specific way to approach into seeing if open closed or isolated?
Replies: 9
Views: 332

Re: Is there a way specific way to approach into seeing if open closed or isolated?

Open system has transfer of heat and material; closed system has transfer of heat but not the transfer of material; isolated system has no transfer of heat or material.
by Melodie Oh 2A
Thu Jan 18, 2018 9:47 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar heat capacity
Replies: 3
Views: 141

Molar heat capacity

I'm still confused about the molar heat capacity. How can the specific heat capacity for gas change depending on the value of volume or pressure?
by Melodie Oh 2A
Wed Jan 10, 2018 4:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 5
Views: 154

Bond Enthalpies

In lecture today, we learned how to use bond enthalpy to calculate ΔH. Just to clarify, does it mean that ΔH= ∑bond broke - ∑bond formed?
by Melodie Oh 2A
Wed Jan 10, 2018 4:28 pm
Forum: Phase Changes & Related Calculations
Topic: Heat and Phase Transition
Replies: 3
Views: 168

Re: Heat and Phase Transition

So basically, the temperature wouldn't change because that heat is required to change the phase. The temperature would stay constant until the phase transitions and then it would start changing its temperature if more heat is given/lost.
by Melodie Oh 2A
Wed Jan 10, 2018 4:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Exothermic reaction in bond enthalpy example in lecture
Replies: 5
Views: 185

Re: Exothermic reaction in bond enthalpy example in lecture

Whenever the enthalpy is negative it is an exothermic reaction as it means that it RELEASES that amount of energy rather than absorbing it.

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