Search found 25 matches

by Michellekim1H
Sun Feb 09, 2020 1:57 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: extensive property
Replies: 12
Views: 118

Re: extensive property

DHavo_1E wrote:Hello,

What would be an example of an intensive property? Thank you!


Intensive properties are properties that don't rely on the amount of substances but the type of matter. Examples would include temperature, color, and density.
by Michellekim1H
Sun Feb 09, 2020 1:50 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeter and Bomb Calorimeter
Replies: 4
Views: 60

Calorimeter and Bomb Calorimeter

I don't know what exactly calorimeters are and I don't know what the differences are either. Can someone please explain how we're also going to use them in problems as well?
by Michellekim1H
Sun Feb 09, 2020 1:45 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Topics on the Midterm
Replies: 22
Views: 229

Re: Topics on the Midterm

I believe we have to review everything from outlines 1-4 including gibbs free energy but anything after that won't be covered in the test.
by Michellekim1H
Sun Feb 09, 2020 1:40 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: solids and liquids in the rxn quotient
Replies: 8
Views: 109

Re: solids and liquids in the rxn quotient

We never include solvents/liquids and solids for K and Q. Only aq and g are accepted.
by Michellekim1H
Tue Feb 04, 2020 11:55 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: Lecture on Feb.3
Replies: 1
Views: 22

Lecture on Feb.3

Can anyone send me notes or tell me what was being taught on February 3? I had to miss class due to an appointment. Thanks in advance!
by Michellekim1H
Sun Feb 02, 2020 8:01 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: adiabatic systems
Replies: 10
Views: 441

Re: adiabatic systems

According to the textbook, it just means that there's o heat transfer between the system and its surroundings even if there's a temperature difference.
by Michellekim1H
Sun Feb 02, 2020 7:50 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible Expansion
Replies: 2
Views: 36

Reversible Expansion

Could someone please explain the concept of this and give an example? Also, are we supposed to know/understand equation involving the integral(for the work of a reversible, isothermal expansion of an ideal gas) that Lavelle showed during class? Or was that just a demonstration of how we got to w = -...
by Michellekim1H
Sat Feb 01, 2020 8:03 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed vs isolated systems
Replies: 24
Views: 198

Re: Closed vs isolated systems

A way to understand the difference between a closed and isolated system could be used by some examples. For a closed system, think of an ice pack. A closed system is defined as a system that exchanges energy with its surroundings but no matter comes out of it. An ice pack is closed but can still exc...
by Michellekim1H
Sat Feb 01, 2020 7:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Self-Test 6A.3A
Replies: 2
Views: 36

Re: Self-Test 6A.3A

Basically, because hydroiodic acid is a strong acid, it dissociates completely in an aqueous solution. This means that the hydronium concentration is equivalent to the initial molarity of the acid. The back of the book represented this value in micromoles, so instead of just writing it as 6.0x10^-5...
by Michellekim1H
Sat Feb 01, 2020 9:57 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Self-Test 6A.3A
Replies: 2
Views: 36

Self-Test 6A.3A

Estimate the concentrations of (a) H3O+ and (b) OH- at 25 C in 6.0 × 10^-5M HI(aq).

The answer for a is 60.μmol⋅L^-1 and for b it's 0.17nmol⋅L^-1. Can someone tell me how to approach this problem?
by Michellekim1H
Sat Jan 25, 2020 12:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Assuming X
Replies: 3
Views: 35

Re: Assuming X

I think for all questions concerning ICE tables, it’s okay to assume that x is an extremely small number if K(Ka, KB, etc) if is less than 10^-3. For this specific type of problem, if x is less than 5% of the initial acid then the approximation should be fine.
by Michellekim1H
Sat Jan 25, 2020 12:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy
Replies: 2
Views: 25

Enthalpy

I’m still having a hard time comprehending what enthalpy is. Could someone please explain to me the concept is in simple terms and possibly even provide an analogy/example?
by Michellekim1H
Sat Jan 25, 2020 12:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: H3O+ < 10^-7 Neutral?
Replies: 1
Views: 27

H3O+ < 10^-7 Neutral?

In lecture, Lavelle had on his slide the following:
Note: If [H3O+] < 10^-7 then the solution is neutral because we know autoprotolysis makes 10^-7 mol/L H3O+.

I don’t understand how this is possible, can someone please explain this to me? Wouldn’t the solution be more basic?
by Michellekim1H
Fri Jan 24, 2020 1:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H
Replies: 10
Views: 360

Re: Delta H

Positive delta H is endothermic(since there’s more energy in the products) whereas negative delta H is exothermic(there’s less energy in the products).
by Michellekim1H
Wed Jan 22, 2020 7:39 pm
Forum: Phase Changes & Related Calculations
Topic: State Property
Replies: 6
Views: 47

State Property

Can someone explain to me the concept of state property? During lecture, I've written down in my notes that state properties can be added or subtracted which I don't understand. Additionally, I've written down that work and heart depend on a path taken and they're not state properties. Can someone p...
by Michellekim1H
Sat Jan 18, 2020 6:59 pm
Forum: Ideal Gases
Topic: Le Chatelier's Principle
Replies: 7
Views: 201

Re: Le Chatelier's Principle

The principle states that reactions adjust to reduce the effects of a changing system. It will basically try to go into equilibrium state. For instance, think about how we can create more products without adding more reactants. We are able to get more products by actually removing them in which the ...
by Michellekim1H
Sat Jan 18, 2020 6:51 pm
Forum: Ideal Gases
Topic: Solids and liquids
Replies: 4
Views: 58

Re: Solids and liquids

Solids and liquids aren't included in the equation because the equation takes into account concentration. It's common sense that solids don't have concentration whereas for liquids, since most are solvents in large excess, it would not really affect the reaction. Therefore, we can just remove solids...
by Michellekim1H
Sat Jan 18, 2020 6:44 pm
Forum: Ideal Gases
Topic: Kp given instead of Kc
Replies: 8
Views: 98

Re: Kp given instead of Kc

First, if given grams, then convert it to moles. Afterwards, input what you have as moles in the ideal gas law equation but rearrange it to get P alone.
by Michellekim1H
Sat Jan 18, 2020 6:30 pm
Forum: Phase Changes & Related Calculations
Topic: Autoprotolysis
Replies: 15
Views: 144

Re: Autoprotolysis

It basically means that a proton is transferred between the same molecule. For example, 2H2O(l) <-> H30+(aq) + OH-(aq).
by Michellekim1H
Sat Jan 18, 2020 6:09 pm
Forum: Ideal Gases
Topic: Topics on Test 1
Replies: 37
Views: 417

Re: Topics on Test 1

The test will cover everything we learned from outlines 1 and 2 (from chemical equilibrium to acids and bases). Anything we learn after that(from week 3) won't appear on the test.
by Michellekim1H
Wed Jan 08, 2020 4:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reaction quotient (Q)
Replies: 3
Views: 42

Re: Reaction quotient (Q)

What happens when Q>K, Q<K, and Q=K, and why? When Q>K: The reaction is favoring the reverse reaction because there’s more products formed. When Q<K: The reaction is favoring the forward reaction because more reactants are made. As a result, it wants to create more products with the excess reactant...
by Michellekim1H
Wed Jan 08, 2020 4:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium Part 2 Post Module #12
Replies: 2
Views: 35

Re: Chemical Equilibrium Part 2 Post Module #12

Consider the following reaction at 1200 K, for which you know Kc = 1.7 x 10-3. Br2 (g) ⇌ 2 Br (g) Your experimental setup is able to measure the equilibrium concentration of Br2 based on its color, but you are unable to measure the concentration of Br directly. If you measure at equilibrium [Br2] t...
by Michellekim1H
Wed Jan 08, 2020 4:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Small K value and Large K value
Replies: 10
Views: 107

Re: Small K value and Large K value

Because K= Products/Reactants, when K > 10^3, this means that products are being favored since K would be large(thus, shifting to the right). When K<10^-3, the reaction favors reactants because K would be small(shifting to the left).
by Michellekim1H
Wed Jan 08, 2020 4:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kp vs Kc
Replies: 9
Views: 97

Re: K vs Kp vs Kc

Kp is only used for partial pressure(for gases) whereas Kc is just the equilibrium constant regarding molar concentrations.
by Michellekim1H
Wed Jan 08, 2020 3:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Are Both L and Aq Excluded From Equilibrium Constant Expressions?
Replies: 4
Views: 52

Are Both L and Aq Excluded From Equilibrium Constant Expressions?

So, I know that solids and liquids are not supposed to be included in Kc but I was wondering if Aq is excluded as well. Isn’t Aq liquid too? Also, I still don’t really understand why these things are excluded from the expression so can someone please explain to me why.

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