## Search found 33 matches

Tue Feb 11, 2020 1:59 am
Forum: Administrative Questions and Class Announcements
Topic: Memorizing acids and bases
Replies: 2
Views: 35

### Memorizing acids and bases

Are we responsible for memorizing strong scids and bases and weak acids and bases?
Tue Feb 11, 2020 1:01 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.39 HW
Replies: 1
Views: 58

### 5.39 HW

In an experiment, 0.020 mol NO was introduced into a 2 flask of volume 1.00 L and the reaction 2 NO2(g) ∆N2O4(g) was allowed to come to equilibrium at 298 K. (a) Using information in Table 5E.2, calculate the equilibrium concentrations of the two gases. (b) The volume of the flask is reduced to half...
Mon Feb 10, 2020 7:17 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5J.1
Replies: 1
Views: 36

### 5J.1

Consider the equilibrium CO(g) 1 H2O(g) ∆CO2(g) 1 H2(g). (a) If the partial pressure of CO2 is increased, what happens to the partial pressure of H2? (b) If the partial pressure of CO is decreased, what happens to the partial pressure of CO2? (c) If the concentration of CO is increased, what happens...
Mon Feb 10, 2020 12:05 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5I.27
Replies: 1
Views: 43

### 5I.27

The equilibrium constant Kc 5 0.56 for the reaction PCl3(g)1 Cl2(g) ∆ PCl5(g) at 250 8C. Upon analysis, 1.50 mol PCl5, 3.00 mol PCl3, and 0.500 mol Cl2 were found to be present in a reaction vessel of volume 0.500 L at 250 8C. (a) Is the reaction at equilibrium? (b) If not, in which direction does i...
Sun Feb 09, 2020 10:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining what’s thermodynamically more stable
Replies: 1
Views: 35

### Determining what’s thermodynamically more stable

Hi! For Homework problem 51.13, part c asked which is thermodynamically more stable relative to its atoms at 1000 K, Cl2 or F2. I know that F2 has a bigger equilibrium constant for dissociation of F2 o F atoms than that of Cl2 to CL atoms. This means that F2 will dissociate more. How do I know which...
Sun Feb 09, 2020 9:20 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Difference between standard reaction enthalpy and enthalpy
Replies: 2
Views: 43

### Re: Difference between standard reaction enthalpy and enthalpy

I’m also confused on what standard enthalpy of formation is
Sun Feb 09, 2020 9:18 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Difference between standard reaction enthalpy and enthalpy
Replies: 2
Views: 43

### Difference between standard reaction enthalpy and enthalpy

How do we now that something is at standard reaction enthalpy. I know that it’s enthalpy at pure form but how do we know that? Do they tell us in the question?
Sat Feb 08, 2020 4:33 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Kw with increasing temperature in endothermic reaction
Replies: 1
Views: 87

### Kw with increasing temperature in endothermic reaction

The autoprotolysis reaction is endothermic; do you expect Kw to increase or decrease with increasing temperature?

Since it’s endothermic, the reaction is absorbing heat so with increasing temperature, Kw would decrease? Is it the same idea as it is for K?
Sat Feb 08, 2020 12:00 am
Forum: Ideal Gases
Topic: Temperature
Replies: 17
Views: 165

### Re: Temperature

Kelvin is usually the units that they ask you for. However, depending on the problem, using kelvin or Celsius would not matter if you are looking for the change between the initial and final
Fri Feb 07, 2020 11:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H.2 Clarifications
Replies: 3
Views: 49

### Re: 5H.2 Clarifications

They simply added the 1st and 2nd equations together and kept the molecules on their respective sides. 2 P(g) + 3 Cl2(g) <—-> 2 PCl3(g) + 2 PCl3(g) + 2 Cl2(g) <—-> 2 PCl5(g) = 2 P + 3 Cl2 + 2 PCl3 + 2 Cl2 <-> 2 PCl3 + 2 PCl5 and you could subtract 2 PCl3 from each side and therefore removing them, ...
Fri Feb 07, 2020 11:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H.2 Clarifications
Replies: 3
Views: 49

### 5H.2 Clarifications

Hi! So I’m reviewing and 5h.2 states hat chemical equations can be expressed as sum of 2 or more chemical equations. The book gave 3 gas phase equations and did the following: 2 P(g) + 3 Cl2(g) <—-> 2 PCl3(g) 2 PCl3(g) + 2 Cl2(g) <—-> 2 PCl5(g) 2 P(g) + 5 Cl2(g) <—-> 2 PCl5(g) So they added the two ...
Thu Feb 06, 2020 4:10 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Explaining Le Chatelier’s principle
Replies: 2
Views: 43

### Explaining Le Chatelier’s principle

Use Le Chatelier's principle to predict how the equilibrium composition of a reaction mixture is affected by: adding or removing reagents; compressing or expanding a gaseous mixture; and by raising or lowering the temperature.

Can someone explain the reasons for the last part?
Wed Feb 05, 2020 3:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: State functions; definition and clarifications
Replies: 3
Views: 53

### State functions; definition and clarifications

Hi! So i understand that a state function is a property that depends on the current state and not the consequent paths to get there. I don’t understand how work and heat are not state functions while internal energy is. Can someone explain that
Sun Feb 02, 2020 3:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Extra Credit
Replies: 7
Views: 177

### Re: Extra Credit

And does anyone know what day the posts reset for points? Would it be every sunday or every Monday?
Sun Feb 02, 2020 3:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Extra Credit
Replies: 7
Views: 177

### Extra Credit

I missed 5 points for the chemistry community. Will there be extra points in the class?
Wed Jan 29, 2020 10:46 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 4a.1
Replies: 3
Views: 56

### 4a.1

Can someone check my answers and help me explain some of these ? A) coffee in a very high quality thermos bottle would be isolated system because the bottle is conserving the heat so its trapped B) coolant in a refrig coil Don’t get what this one means C) a bomb calorimeter in which benzene is burne...
Wed Jan 29, 2020 10:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Define Reversible process
Replies: 2
Views: 63

### Define Reversible process

So, from what Ive read on the textbook, a reversible process means any small change can cause the object working against opposing force to move in or out? Also, can someone explain what this means? Expansion against external pressure that differs by a measurable amount from the pressure of the syste...
Wed Jan 22, 2020 6:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.21
Replies: 1
Views: 33

### 6A.21

Is the answer the same for both a and b, which would be 6.8 since x= 1.45*10^-7 and [H3O]=[OH-]
Wed Jan 22, 2020 1:06 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: POST ASSESSMENT PART 1B NUMBER 27
Replies: 1
Views: 26

### POST ASSESSMENT PART 1B NUMBER 27

27. A mixture of 2.5 moles H2O and 100 g of C are placed in a 50 L container and allowed to come to equilibrium subject to the following reaction: C(s) + H2O (g) ⇌ CO (g) + H2 (g) The equilibrium concentration of hydrogen is found to be [H2] = 0.040 M. What is the equilibrium concentration of water,...
Tue Jan 21, 2020 9:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Assessment PART 1B NUMBER 47
Replies: 1
Views: 33

### Post Assessment PART 1B NUMBER 47

47. The reaction 2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g) occurs in a 1.00 L flask at 312 K and at equilibrium the concentrations are 0.075 mol.L-1 SO2 (g), 0.537 mol.L-1 O2 (g), and 0.925 mol.L-1 SO3 (g). Calculate their respective partial pressures at 312 K using R = 8.206 × 10-2 L.atm.K-1.mol-1. A. Pso2 = ...
Tue Jan 21, 2020 9:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Assessment Part 1B number 18
Replies: 1
Views: 14

### Post Assessment Part 1B number 18

Question 18 asks that we find the equilibrium constant given an equilibrium reaction and the partial pressures (in Bars) at 500 K.

It doesn’t specify to find Kp or Kc. Do I assume that it is asking for Kp so I would not need to convert or Kc, by which means I have to convert?
Tue Jan 14, 2020 5:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Including gasses for Q vs K
Replies: 2
Views: 33

### Including gasses for Q vs K

Hi, so I was doing 5g.11 and I got confused about gas phases. So for K, there’s Kc and Kp, and you use Kp for partial pressures for gas phases right while you use Kc for aq.

Why is it that you are solving for the concentration of the gas for Q but the partial pressure of gas for Kp?
Tue Jan 14, 2020 4:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G 9 HW C VS. D AND E
Replies: 2
Views: 49

### 5G 9 HW C VS. D AND E

Hi! Can someone explain why c wouldn’t be the same? I know that d and e are the same in both containers because they’re the ratio of the equilibrium constant and the reverse of it, but what about C? The only explanation I thought of was that c isn’t in a balanced equation so it can’t reach equilibri...
Tue Jan 14, 2020 3:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5g.3 b HOMEWORK
Replies: 2
Views: 44

### 5g.3 b HOMEWORK

Hi! For the b part, you have to balance the equation first before you write the expression for K right?

How would you balance the eq?
4NH3 + 6NO — 7N2 + 6H20
Tue Jan 14, 2020 2:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.1 d homework
Replies: 1
Views: 21

### 5G.1 d homework

Would d be true because you are not changing the K value of the concentration at equilibrium and to achieve that k value, you would need a higher equilibrium concentration of product to keep it balanced?
Tue Jan 14, 2020 2:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 5g.1 B
Replies: 2
Views: 31

### Homework 5g.1 B

When you increase the concentrations of products, is the equilibrium reaction affected? I know that the value of K does not change, so can I say that the position of the reaction rate Q changes relative to K? Would that make the statement true?
Tue Jan 14, 2020 9:54 am
Forum: Student Social/Study Group
Topic: Office Hours
Replies: 5
Views: 200

### Re: Office Hours

No, but I’ve been to a UA’s workshop (Lyndon) and he basically gives out a worksheet and go over it.
Tue Jan 14, 2020 9:51 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature change
Replies: 5
Views: 34

### Re: Temperature change

If the temperature increases, would the value of K increase too?
Fri Jan 10, 2020 10:18 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between -> and <->
Replies: 4
Views: 58

### Re: Difference between -> and <->

When calculating Q, you are only going in one direction because Q could be calculated regardless of whether or not the reaction is in equilibrium.
Thu Jan 09, 2020 2:05 pm
Forum: Administrative Questions and Class Announcements
Topic: 6th edition and homework problems
Replies: 3
Views: 53

### 6th edition and homework problems

So I have the 6th edition of the textbook. Do I need to buy the 7th edition because I can’t find the homework problems that he listed. If anyone else have the 6th edition, what page and problems would it be?
Thu Jan 09, 2020 1:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K being small or large
Replies: 4
Views: 34

### Re: K being small or large

When K is greater than a 1000, the reaction strongly favors the products. Therefore, the reaction lies to the right so there will be very little forward reaction. When K is less than 10^-3, the reaction strongly favors the reactants. Therefore, the reaction lies to the left so the reaction would b c...
Thu Jan 09, 2020 1:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q versus K
Replies: 4
Views: 54

### Re: Q versus K

Q is the reaction quotient and has the same formula as K. Q would be equal to the concentrations of the product over the concentrations of the reactants. However, unlike K, Q can be used even when the equation isn’t in equilibrium. You then use Q and compare it to K to see how far the reaction is fr...
Thu Jan 09, 2020 1:19 pm
Forum: Ideal Gases
Topic: Calculating K when there is multiple phases
Replies: 4
Views: 57

### Calculating K when there is multiple phases

What do you do when the equilibrium equation includes both aqueous and gas phases? Do you solve for each independently and somehow add them or do you convert?