Search found 44 matches

by Andy Hon 3E
Fri Feb 26, 2021 6:38 pm
Forum: Balancing Redox Reactions
Topic: Acidic vs. Basic
Replies: 20
Views: 34

Re: Acidic vs. Basic

For acidic, you would use H+ to balance out the equation while for basic, it would be OH-
by Andy Hon 3E
Fri Feb 26, 2021 6:35 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing vs Reducing
Replies: 55
Views: 124

Re: Oxidizing vs Reducing

The way I remember it is OIL RIG as well. As far as oxidizing and reducing agents, I always remember it like they are opposites in that the oxidizing agent is the one getting reduced and the reducing agent is the one getting oxidized.
by Andy Hon 3E
Fri Feb 26, 2021 6:30 pm
Forum: Administrative Questions and Class Announcements
Topic: When is Sapling HW due?
Replies: 22
Views: 67

Re: When is Sapling HW due?

It is due this Sunday by midnight!
by Andy Hon 3E
Fri Feb 26, 2021 6:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14 B Final
Replies: 34
Views: 154

Re: Chem 14 B Final

I checked the syllabus, and the final will be cumulative.
by Andy Hon 3E
Tue Feb 23, 2021 12:10 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sig Figs
Replies: 7
Views: 27

Re: Sig Figs

yes they do
by Andy Hon 3E
Tue Feb 23, 2021 12:09 am
Forum: Student Social/Study Group
Topic: Chem 14B Final
Replies: 83
Views: 211

Re: Chem 14B Final

I would rewatch lectures on topics that were a bit confusing to get a better understanding and also look at sapling hw qs.
by Andy Hon 3E
Fri Feb 19, 2021 2:50 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: When does delta H = q?
Replies: 15
Views: 47

Re: When does delta H = q?

It's because it has constant pressure when delta H= q.
by Andy Hon 3E
Fri Feb 19, 2021 2:48 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Delta U in different systems
Replies: 4
Views: 25

Re: Delta U in different systems

I also think that Delta U=w+q can be used in an open system, but I'm not too sure what you would account for. What was said above about taking into inconsideration changes in mass in the open system makes sense, however.
by Andy Hon 3E
Fri Feb 19, 2021 2:43 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Is thermal mugs an example of an isolated system?
Replies: 30
Views: 66

Re: Is thermal mugs an example of an isolated system?

Yes! That would be an example of an isolated system. Although some heat and energy may be scaping through pressure holes etc, it is a good example concept-wise.
by Andy Hon 3E
Fri Feb 19, 2021 2:40 pm
Forum: Phase Changes & Related Calculations
Topic: calculating phase change
Replies: 6
Views: 29

Re: calculating phase change

Yes adding ndelta H to q is the way to find the heat required for phase change.
by Andy Hon 3E
Fri Feb 19, 2021 2:34 pm
Forum: Calculating Work of Expansion
Topic: Work sign
Replies: 39
Views: 82

Re: Work sign

If the system is the one doing the work, then it will have a negative sign in front of it. However, if work is being performed on the system then, work will be positive.
by Andy Hon 3E
Mon Feb 15, 2021 9:02 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook 4C.9a
Replies: 5
Views: 18

Re: Textbook 4C.9a

1.45x10^2
by Andy Hon 3E
Mon Feb 15, 2021 9:00 pm
Forum: Calculating Work of Expansion
Topic: Sign of work
Replies: 25
Views: 53

Re: Sign of work

Work is positive with the addition of energy in the system. Work is negative when it is the system itself doing the work.
by Andy Hon 3E
Mon Feb 15, 2021 8:57 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: m versus n
Replies: 11
Views: 66

Re: m versus n

m= mass
n= moles
by Andy Hon 3E
Thu Feb 11, 2021 2:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling Week 3/4 Question 18
Replies: 9
Views: 70

Re: Sapling Week 3/4 Question 18

I used deltaU=nCVT as well!
by Andy Hon 3E
Thu Feb 11, 2021 2:35 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Can heat capacities be negative?
Replies: 52
Views: 159

Re: Can heat capacities be negative?

Heat capacities cannot be negative because you are inputting energy into a reaction not taking it away.
by Andy Hon 3E
Thu Feb 11, 2021 2:34 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q equation
Replies: 21
Views: 53

Re: q equation

m is used when you have grams in the question. If there is n it is for moles.
by Andy Hon 3E
Thu Feb 11, 2021 2:32 pm
Forum: Phase Changes & Related Calculations
Topic: Boiling water
Replies: 25
Views: 108

Re: Boiling water

When there are hydrogen bonds, it is the reason water is in its liquid state. When water is boiled, the hydrogen bonds are broken and changed into vapor.
by Andy Hon 3E
Thu Feb 11, 2021 2:28 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Free Energy
Replies: 41
Views: 130

Re: Free Energy

You must look at the final and initial states
by Andy Hon 3E
Thu Feb 04, 2021 2:44 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: W
Replies: 14
Views: 65

Re: W

2^4 is correct because n represents the number of molecules in the system.
by Andy Hon 3E
Thu Feb 04, 2021 2:41 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Work
Replies: 39
Views: 110

Re: Work

Yes just to reiterate, work done on its own will have negative work because it requires energy, while work that is acted on the system will be positive.
by Andy Hon 3E
Wed Feb 03, 2021 10:08 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Solving for Cubic Equations
Replies: 13
Views: 33

Re: Solving for Cubic Equations

I was reviewing some of the lectures and the example that was used for the weak acid problem was to calculate the percent ionization, which is the final product over its initial (not at equilibrium) value. If the percentage was less than 5 percent then approximating was valid.
by Andy Hon 3E
Wed Feb 03, 2021 12:27 am
Forum: Phase Changes & Related Calculations
Topic: X2 vs 2X
Replies: 14
Views: 74

Re: X2 vs 2X

The reaction is endothermic because it requires energy to break bonds. In this case, the end result is two separate x's so 2x
by Andy Hon 3E
Tue Feb 02, 2021 11:07 pm
Forum: Ideal Gases
Topic: Reversing Reactions
Replies: 24
Views: 81

Re: Reversing Reactions

When you reverse a reaction, the k value will simply be the inverse of the original forward reaction. 1/k or k^-1
by Andy Hon 3E
Sat Jan 30, 2021 1:27 am
Forum: Phase Changes & Related Calculations
Topic: when to assume x is insignificant
Replies: 83
Views: 193

Re: when to assume x is insignificant

You can approximate x, when its Ka or Kb value is less than 10^-4.
by Andy Hon 3E
Sat Jan 30, 2021 1:24 am
Forum: Phase Changes & Related Calculations
Topic: Examples of sublimation
Replies: 12
Views: 77

Re: Examples of sublimation

Dry ice is an excellent example of sublimation, where condensed carbon dioxide becomes vapor.
by Andy Hon 3E
Wed Jan 27, 2021 12:52 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Chart Question
Replies: 16
Views: 86

Re: ICE Chart Question

You would leave it in because the -2x gives you the equilibrium concentration. You use that equation to plug it into the equilibrium constant equation. You would still have to square it or raise it to its stoichiometric coefficient.
by Andy Hon 3E
Tue Jan 26, 2021 11:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Finding Ka from pH
Replies: 7
Views: 49

Re: Finding Ka from pH

correction for the typo above its 10^-ph
by Andy Hon 3E
Tue Jan 26, 2021 11:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Finding Ka from pH
Replies: 7
Views: 49

Re: Finding Ka from pH

Agreed ^ You would first have to use the pH to find the H+ value. Since pH= -log[H+] then H+= -10^pH. From there you can put the H+ in the Ka equilibrium equation along with given concentration in the problem and solve.
by Andy Hon 3E
Fri Jan 22, 2021 10:23 pm
Forum: Ideal Gases
Topic: Inverse Kc [ENDORSED]
Replies: 41
Views: 123

Re: Inverse Kc [ENDORSED]

Kc is used in the forward reaction and Kc^-1 is used in the inverse reaction.
by Andy Hon 3E
Thu Jan 21, 2021 12:30 am
Forum: Phase Changes & Related Calculations
Topic: Steam vs. Water
Replies: 9
Views: 63

Re: Steam vs. Water

Since steam coming in contact with the skin will turn into a liquid, the reaction will release a high amount of energy in the form of heat. The higher the enthalpy of vaporization is, the more energy a gas has, and thus more energy to be released.
by Andy Hon 3E
Thu Jan 21, 2021 12:23 am
Forum: Phase Changes & Related Calculations
Topic: Vapor vs gas
Replies: 92
Views: 249

Re: Vapor vs gas

Vapor and gas can be used the same way.
by Andy Hon 3E
Thu Jan 21, 2021 12:22 am
Forum: Ideal Gases
Topic: Equilibrium Constant (Q and K)
Replies: 13
Views: 73

Re: Equilibrium Constant (Q and K)

The Equation for both Q and K is the concentration of products over the concentration of reactants. However, K is the equilibrium constant, and Q is the reaction quotient which is the value not in equilibrium at any time during the reaction.
by Andy Hon 3E
Tue Jan 19, 2021 3:10 pm
Forum: Ideal Gases
Topic: Sampling hw #4
Replies: 16
Views: 180

Re: Sampling hw #4

My initial thought was to also switch the equation so that PCl5 is on the left and the rest of the equation on the right to show reactants to products. However, the only way to get the correct answer was the say leave PCl 5 as the product and divide it by reactants.
by Andy Hon 3E
Sat Jan 16, 2021 6:03 pm
Forum: Ideal Gases
Topic: Q and K relationship
Replies: 22
Views: 129

Re: Q and K relationship

Since Q and K are calculated the same way, if Q is less than K, this means that DURING the reaction there are more reactants than products because (a greater denominator for reactants means a smaller number). Therefore, in order for the system to reach/return to equilibrium, the greater number of re...
by Andy Hon 3E
Wed Jan 13, 2021 9:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Salts
Replies: 5
Views: 39

Re: Salts

Salt was used as an example to show its neutrality since it is composed of cations and anions.
by Andy Hon 3E
Wed Jan 13, 2021 9:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Lecture Question
Replies: 9
Views: 95

Re: Lecture Question

Rewatched the lecture and can confirm that Dr. Labelle accidentally misspoke.
by Andy Hon 3E
Mon Jan 11, 2021 11:52 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O as a Gas
Replies: 69
Views: 454

Re: H2O as a Gas

When water is considered a liquid (essentially the solvent in the equation), the concentration of liquids does not change significantly to say it has changed in cc. However, when water is considered a gas, it is variable and can change.
by Andy Hon 3E
Mon Jan 11, 2021 11:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7342

Re: Accessing the E-textbook [ENDORSED]

For anyone that is wondering why they possibly have not received Sapling access code. It is possible that the shipping option you chose was the "pick up at ucla" (in order to check out, they made you choose a shipping option even though its an ebook). I called Ackerman and they simply said...
by Andy Hon 3E
Thu Jan 07, 2021 2:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7342

Re: Accessing the E-textbook [ENDORSED]

When you re-purchased, did you receive a code on email or were you able to access it right away? I still for some reason unable to get into sapling.
by Andy Hon 3E
Wed Jan 06, 2021 7:11 pm
Forum: Ideal Gases
Topic: What makes an ideal gas an ideal gas?
Replies: 9
Views: 72

Re: What makes an ideal gas an ideal gas?

The property of an ideal gas is that it does not change phase and no intermolecular forces. The ideal gas law is theoretical concept but is applicable to most real gases.
by Andy Hon 3E
Wed Jan 06, 2021 7:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7342

Re: Accessing the E-textbook [ENDORSED]

I purchased the sapling+ 7th edition ebook a few days ago from ucla and have not received a notification for the prepaid code to access sapling. Does anybody have a solution or are in a similar situation? Thanks.
by Andy Hon 3E
Wed Jan 06, 2021 6:57 pm
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 109
Views: 999

Re: Kc vs Kp

Kc should be used when questions give the concentration in mol/liter and Kp is for partial pressure. However, there is an equation to convert between the two if need be.
by Andy Hon 3E
Tue Jan 05, 2021 11:49 am
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Posts in 14B
Replies: 156
Views: 2342

Re: Chemistry Posts in 14B

Hi this is also my first time using this forum. Are we allowed to create a new topic/discussion page or are we limited to the ones already created under the board index under 14b? Thank you

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