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CHM1046 Quizzes

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Title: Chapter 12 new quiz Started: January 16, 2010 2:20 PM Submitted: January 16, 2010 3:04 PM Time spent: 00:44:52 Total score: 9.05/10 = 90.5% Total score adjusted by 0.0 Maximum possible score: 10 1 . Calculate the weight percent of a solution made by mixing 72.1 g of sucrose, C 12 H 22 O 11 , in 495.65 g of water. Submit your answer to 2 decimal places. Student Response Value Correct Answer Answer : 12.70 100% 12.70 Units: % 0.0% % Score: 1/1 2 . Calculate the weight percent of a solution made by mixing 5.00 g of urea, (NH 2 ) 2 CO in 67.02 g of water. Submit your answer to 2 decimal places. Student Response Value Correct Answer Answer : 6.94 100% 6.94 Units: % 0.0% % Score: 1/1 3 .
Transcript
Page 1: CHM1046 Quizzes

Title: Chapter 12 new quizStarted: January 16, 2010 2:20 PMSubmitted: January 16, 2010 3:04 PMTime spent: 00:44:52

Total score: 9.05/10 = 90.5% Total score adjusted by 0.0 Maximum possible score: 10

1.

 

Calculate the weight percent of a solution made by mixing 72.1 g of sucrose, C12H22O11, in 495.65 g of water. Submit your answer to 2 decimal places.

  Student Response Value Correct AnswerAnswer: 12.70   100% 12.70Units: % 0.0% %

Score: 1/1

 

2.

 

Calculate the weight percent of a solution made by mixing 5.00 g of urea, (NH2)2CO in 67.02 g of water. Submit your answer to 2 decimal places.

  Student Response Value Correct AnswerAnswer: 6.94   100% 6.94Units: % 0.0% %

Score: 1/1

 

3.

 

Calculate the mole fraction of a solution made by mixing 32.9 g of sucrose, C12H22O11, in 136.86 g of water. Submit your answer to 3 decimal places.

  Student Response Value Correct AnswerAnswer: 0.012   100% 0.012

Score: 1/1

 

4.  Calculate the molality of a solution made by mixing 15.2 g of urea, (NH2)2CO in 393.95 g of water.

Page 2: CHM1046 Quizzes

Submit your answer to 3 decimal places.

  Student Response Value Correct AnswerAnswer: 0.642   95% 6.42E-1 (6.42 × 10-1)Units: m 5.0% m

Score: 1/1

 

5.

 

Calculate the molality of a solution made by mixing 14.8 g of urea, (NH2)2CO in 459.18 g of water. Submit your answer to 3 decimal places.

  Student Response Value Correct Answer

Answer: 0.537   95% 0.537

Units: m 5.0% m

Score: 1/1

 

6.

 

You are given an aqueous 20.0 m solution of ammonia, NH3. What is the weight percent of the solution?

  Student Response Value Correct AnswerAnswer: 25.4%   100% 25.4

Score: 2/2

 

7.

 

You are given a 89.0% solution of sulfuric acid, H2SO4. What is the molality of this solution? The density of the H2SO4 solution is 1.610 g/mL.

  Student Response Value Correct AnswerAnswer: 82.5   95% 82.5

Units: m 5.0% m

Score: 2/2

 

Page 3: CHM1046 Quizzes

8.

 

Calculate the molality of ions in a solution made by mixing 6.32 g of KBr, MW=119.00, in 60.44 mL of water at 37.0°C. The density of water at this temperature is 0.9933 g/cm-3 Submit your answer to 2 decimal places.

  Student Response Value Correct AnswerAnswer: 0.88   0% 1.77Units: m 5.0% m

Score: 0.05/1

 

Title: Chapter 13 new quizStarted: April 16, 2010 6:42 PMSubmitted: April 16, 2010 7:03 PMTime spent: 00:20:31

Total score: 8/10 = 80% Total score adjusted by 0.0 Maximum possible score: 10

1.

 

A reaction with the activation energy Ea= 219.00 kJ/mol, has a rate constant k = 1.400 x 102 at 988.00 Kelvin. Determine the rate constant when the temperature is changed to 238.00 Kelvin. R = 8.314 J K-1mol-1

  Student Response Correct AnswerAnswer: 4.56E-35   4.56E-35 (4.56 × 10-35)

General Feedback:

Rearrange the two-temperature Arrhenius equation as shown on p507 of MF 3rd Edition and solve for k2

Score: 2/2

 

2.  Calculate the half life of a first order reaction having a rate constant of 5.16 x 10-4. Enter your

answer to 3 sig figs.

  Student Response Correct AnswerAnswer: 1.34E3   1.34E3 (1.34 × 103)

Score: 1/1

Page 4: CHM1046 Quizzes

 

3.

 

The rate constant for the decomposition of dinitrogen pentoxide to form nitrogen dioxide and oxygen gas has the rate constant 1.7 x 10-3 s-1. This is a first order reaction. How long would it take for for the reaction to be 89.00% to complete? Enter your answer to 1 decimal place even if that is more sig figs that you are entitled to report.

  Student Response Correct AnswerAnswer: 1298.4   1,298.4

General Feedback:

Apply the first order integrated rate equation rearranged to solve for t, with the initial concentration as [A]o and the final concentration as [A]t.

Score: 1/1

 

4.

 

The rate constant for the decomposition of dinitrogen pentoxide to form nitrogen dioxide and oxygen gas has the rate constant 1.7 x 10-3 s-1. This is a first order reaction. If the initial concentration of dinitrogen pentoxide was 1.318 mol/L, how many seconds will it take for the concentration to reach 0.461 mol/L?

  Student Response Correct AnswerAnswer: 617.9   618

General Feedback:

Apply the first order integrated rate equation rearranged to solve for t, with the initial concentration as [A]o and the final concentration as [A]t.

Score: 1/1

 

5.  In a certain decomposition reaction, dinitrogen pentoxide decomposes to form nitrogen dioxide gas

and oxygen gas. It was found that at 189 seconds the concentration of oxygen gas was 0.296 mol/L and at 764.8 seconds the concentration of oxygen gas was 0.625 mol/L. What is the rate of decomposition of dinitrogen tetroxide over the specified time period in this reaction?

  Student Response Correct AnswerAnswer: 1.14E-3   -1.14E-3 (-1.14 × 10-3)

General The rate of a reaction is the rate of change of some species. In this case we are measuring

Page 5: CHM1046 Quizzes

Feedback:

the change in concentration with time. To solve this, we divide the change in concentration by the time taken for the change to occur. The units are M/s. See page 475 of your textbook.

Score: 0/1

 

6.

 

In a certain decomposition reaction, dinitrogen pentoxide decomposes to form nitrogen dioxide gas and oxygen gas. It was found that at 399 seconds the concentration of oxygen gas was 0.420 mol/L and at 715.4 seconds the concentration of oxygen gas was 0.967 mol/L. What is the rate of formation of nitrogen dioxide over the specified time period in this reaction?

  Student Response Correct AnswerAnswer: 3.46E-3   6.92E-3 (6.92 × 10-3)

General Feedback:

The rate of a reaction is the rate of change of some species. In this case we are measuring the change in concentration with time. To solve this, we divide the change in concentration by the time taken for the change to occur. The units are M/s. See page 475 of your textbook.

Score: 0/1

 

7.

 

The second order rate constant for a reaction is 3.2100 x 102 M-1s-1. If the initial reagent concentration is 0.93100 mol/L, determine the time (in seconds) required for the reagent concentration to reach 0.34600 mol/L.

  Student Response Correct AnswerAnswer: 5.66E-3   0.01

General Feedback:

Apply the second order integrated rate equation rearranged to solve for t .

Score: 1/1

 

8.  Determine the activation energy Ea in kJ/mol for a reaction who's rate constant k1 = 4.400 x 10-6 at

471.00 Kelvin changes to k2 = 7.500 x 10-2 when the temperature is changed to 625.00 Kelvin. R = 8.314 J Enter your answer in kJ.K-1mol-1

Page 6: CHM1046 Quizzes

  Student Response Correct AnswerAnswer: 1.55E2   1.55E2 (1.55 × 102)

General Feedback:

Rearrange the two-temperature Arrhenius equation as shown on p507 of MF 3rd Edition and solve for Ea.

Score: 1/1

 

9.

 

A reaction with the activation energy Ea= 92.00 kJ/mol, has a rate constant k = 8.500 x 10-4 at 379.00 Kelvin. Determine the temperature required to increase the rate constant 5 times . R = 8.314 J K-1mol-1

  Student Response Correct AnswerAnswer: 4.01E2   4.01E2 (4.01 × 102)

General Feedback:

Rearrange the two-temperature Arrhenius equation as shown on p507 of MF 3rd Edition and solve for T2

Score: 1/1

 

Chapter 14 new quizStarted: February 22, 2010 9:43 PMSubmitted: February 22, 2010 10:03 PMTime spent: 00:20:32

Total score: 10/10 = 100% Total score adjusted by 0.0 Maximum possible score: 10

1.  The reaction

2 B(aq) + D(aq) A(aq) + 2 F(aq)

is currently found, in some aqueous mixture at 22oC, to be at equilibrium. Placing the reaction vessel in ice water causes an increase in B and D concentration, thus:

Page 7: CHM1046 Quizzes

  Student Response Correct AnswerA. the reaction shown must be endothermic.   B. the rate of the forward reaction must be less than the rate of the reverse

reaction. 

C. the concentration of A must be equal to the concentration of D.   D. the rate of the forward reaction must be exactly equal to the rate of the

reverse reaction. 

E. The reaction must be exothermic.  

Score: 1/1

 

2.

 

The reaction

2 B(aq) + D(aq) A(aq) + 2 F(aq)

may be, in some aqueous mixture at 22oC, at equilibrium. If Q < K, you could definitely say that:

  Student Response Correct AnswerA. the reaction shown must be endothermic.   B. the rate of disappearance of B is exactly one-half the rate of gain of A.   C. the rate of the forward reaction must be exactly equal to the rate of the

reverse reaction. 

D. the rate of the forward reaction is not equal the rate of the reverse reaction.

 

E. the concentration of A must be equal to the concentration of D.  

Score: 1/1

 

3.

 

A mixture of 0.100 mol of CO2, 0.050 mol of H2, and 0.100 mol of H2O is placed in a 1.00 L vessel and reacts according to the reaction shown below.

CO2 + H2 --> CO + H2O (all are gaseous)

At equilibrium the container is found to contain 0.0916 M CO2. What is the equilibrium constant, Kc, for the reaction?

  Student Response Correct AnswerAnswer: 0.24   0.239

Score: 1/1

 

Page 8: CHM1046 Quizzes

4.

 

The chemical reaction

2 D(g) + F(g) 2 B(g)

for which Kp = 14.83 and Ho = 22.6 kJ/mol, is initially at equilibrium in a sealed 3.000 L adjustable volume vessel at 25oC. Altering conditions may cause the reaction to shift in order to reach a new equilibrium. What kind of adjustment is expected of the reaction if the following changes are made? (The answers are listed as effect of A; effect of B)

A. increased the volume of the vessel

B. decreased the temperature of the system ?

  Student Response Correct AnswerA. shift right; shift right   B. shift left; shift left   C. shift ldft; shift right   D. shift right; shift left   E. no shift; shift left  

Score: 1/1

 

5.

 

Initially, .500 atm of H2 and .500 atm I 2 are mixed in an evacuated 1.0 L flask. The system is allowed to come to equilibrium and it is found tocontain 0.320 atm HI. What is the equilibrium partial pressure of I2 for the reaction shown below?

H2 + I2 --> 2 HI

  Student Response Correct AnswerAnswer: 0.340   0.340

Score: 1/1

 

6.  The reaction

A(s) + 2 B(g) 2 D(g)

Page 9: CHM1046 Quizzes

exhibits Kc = 0.0277 at 342 K. If the standard enthalpy change for this reaction is 10.0 kJ/mol, what is the value of Kc for the following reaction ?

D(g) B(g) + 1/2 A(s)

  Student Response Correct AnswerAnswer: 6.01   6.01

Score: 1/1

 

7.

 

A mixture of A(aq) and B(aq) associated with the reaction

A(aq) 2 B(aq)

for which the numerical value of Kc is 4.26, is initially prepared to contain [A] = 0.500 M and [B] = 1.81 M. As this system progresses toward equilibrium, we can confidently predict

  Student Response Correct AnswerA. the concentrations of both A and B will decrease.   B. the concentration of A will increase, while the concentration of B will

decrease. 

C. no change will occur in the concentration of either A or B.   D. the concentrations of both A and B will increase.   E. the concentration of A will decrease, while the concentration of B will

increase. 

Score: 1/1

 

8.  Given the chemical reaction

3 A(g) + 2 B(s) 2 D(g)

What is the equilibrium constant, Kp, expression for the reverse reaction?

  Student Response Correct AnswerA.  

B.  

Page 10: CHM1046 Quizzes

  Student Response Correct AnswerC.  

D.  

E.  

Score: 1/1

 

9.

 

Under a set of unspecified conditions, the reaction

H2(g) + O2(g) + Cl2(g) 2 HOCl(g)

has Kp = 0.0698. What is the value of Kp for the reverse reaction ?

  Student Response Correct AnswerAnswer: 14.3   14.3

Score: 1/1

 

10.

 

Kp = 0.233 for the following reaction at 470° C.

A (g) + B (s) = 2 C (g)

What is the correct value of Kc? Enter your answer to 4 decimal places. e.g. 0.0025

  Student Response Correct AnswerAnswer: 0.0038   0.0038

Score: 1/1

Title: Chapter 16 new quizStarted: April 16, 2010 7:04 PMSubmitted: April 16, 2010 7:26 PMTime spent: 00:22:16

Total score: 8/10 = 80% Total score adjusted by 0.0 Maximum possible score: 10

1. Buffer Calculation 1

Page 11: CHM1046 Quizzes

 

Calculate the pH of a buffer solution made by mixing 34 ml of a 0.11 M potassium acetate solution with 65 ml of a 0.10M acetic acid solution. Give the pH to two decimal places.

  Student Response Value Correct AnswerAnswer: 4.50   100% 4.50

Score: 1/1

 

2. Buffer Conceptual 2

 

Which of the following combonations will result in the creation of a buffer? Select all that apply.

 Student

ResponseValue

Correct Answer

Feedback

A. mixing 0.50 mol NaOH with 1.0 mol HOBr

50%   good!  

B. mixing 0.25 mol HCl with 1.0 mol CH3NH2

50%   Good!  

C. mixing 0.50 mol HCl with 1.0 mol HOBr

   

D. mixing 1.0 mol HCl with 0.50 mol NH3

   

E. mixing 0.50 mol NaOH with 0.50 mol HOBr

   

Score: 1/1

 

Page 12: CHM1046 Quizzes

3. Buffer Conceptual 1

 

Which of the following combonations will result in the creation of a buffer? Select all that apply.

 Student

ResponseValue

Correct Answer

Feedback

A. mixing 0.50 mol HCl with 1.0 mol NH3

50%   good!  

B. mixing 0.50 mol HCl with 0.50 mol NH3

   

C. mixing 1.0 mol HCl with 0.50 mol NH3

   

D. mixing 0.50 mol HCl with 1.0 mol NH4Cl

   

E. mixing 0.25 mol NaOH with 1.0 mol HF

50%   Good!  

Score: 1/1

 

4. Buffer Mixture 2

 

Calculate the pH of a buffer solution made by mixing 31.1 g of potassium formate into 1 L of a 0.09 M solution of formic acid. Give the pH to two decimal places.

  Student Response Value Correct AnswerAnswer: 4.36   100% 4.35

Score: 1/1

 

5. Buffer of pH 4

Page 13: CHM1046 Quizzes

 

Which of the following sets of conjugate pairs would you select to make a buffer with a pH of 3.35?

 Student

ResponseValue

Correct Answer

Feedback

A. nitrous acid and sodium nitrite

   

B. lactic acid and sodium lactate

   

C. hydrazine and hydrazinium +1

0%    

D. benzoic acid and sodium benzoate

   

E. arsenious acid and sodium arsenate

   

Score: 0/1

 

6. Buffer of pH 1  Which of the following sets of conjugate pairs would you select to make a buffer with a

pH of 9.22? Select one answer.

 Student

ResponseValue

Correct Answer

Feedback

A. arsenious acid and sodium arsenate

0%    

B. benzoic acid and sodium benzoate

   

C. ammonia and ammonium chloride

   

D. nitrous acid and sodium nitrite

   

Page 14: CHM1046 Quizzes

 Student

ResponseValue

Correct Answer

Feedback

E. hydrazine and hydrazinium +1

   

Score: 0/1

 

7. Equivalence point

 

Calculate the volume of .025 M HCl required to titrate 50.0 mL of 0.046M NaOH solution to the equivalence point. State your answer to one decimal place in mL.

  Student Response Value Correct AnswerAnswer: 92.0    100% 92.0

Score: 1/1

 

8. SA/SB titration 2

 

Calculate the pH of a solution resulting from the titration of 50mL of 0.044M HBr with 25 mL of 0.102M KOH. Give your answer to two decimal places.

  Student Response Value Correct AnswerAnswer: 11.67   100% 11.67

Score: 1/1

 

9. WA SB Titration pKa pt

 

What is the pH of a solution resulting from the titration of 50 mL of 0.050 M formic acid solution, HCOOH, with 25 mL of 0.050 M NaOH solution? Calculate your answer to two decimal places.

 Student

ResponseValue

Correct Answer

Feedback

A. pH = 2.90    B. pH = 3.74 100%   easy, wasn't it!  C. pH = 2.60    D. pH = 6.01    

   

Title: Chapter 17 new quiz

Page 15: CHM1046 Quizzes

Started: April 3, 2010 12:59 PMSubmitted: April 3, 2010 1:06 PMTime spent: 00:07:23

Total score: 8.02/10.02 = 80.0399% Total score adjusted by 0.0 Maximum possible score: 10.02

1. Question 107

 

Under which of the following conditions would one mole of Ne have the highest entropy, S?

 Student

ResponseValue Correct Answer Feedback

A. 27 C and 25 L

   

B. 137 C and 25 L

   

C. 27 C and 35 L

   

D. 137 C and 35 L

100%    

Score: 1/1

 

2. Question 103  The following pictures represent three equilibrium mixtures for the interconversion of A, B, and C

molecules (unshaded spheres) into X, Y, and Z molecules (shaded spheres), respectively. What is

the sign of G for each of the three reactions?

 Student

ResponseValue Correct Answer Feedback

A. G

(1) =

-; G

(2) =

+; G

   

Page 16: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

(3) = 0

B. G

(1) =

-; G

(2) =

0; G

(3) = +

100%    

C. G

(1) =

0; G

(2) =

-; G

(3) = +

   

D. G

(1) =

+; G

(2) =

0; G

(3) = -

   

Score: 1/1

 

3. Question 096  Consider the reaction 2A(g) A2(g). The following pictures represent two possible initial states and

Page 17: CHM1046 Quizzes

the equilibrium state of the system.

What are the signs (+ or -) of H, S, and G when the system goes from initial state 2 to the equilibrium state?

 Student

ResponseValue Correct Answer Feedback

A. H =

+, S =

+, G = +

   

B. H =

+, S =

+, G = -

0%    

C. H = -,

S = -,

G = +

   

D. H = -,

S = -,

G = -

   

Score: 0/1

 

4. Question 085  In figure (1) below oxygen molecules, represented by unshaded spheres, and chlorine molecules,

represented by shaded spheres, are in separatecompartments. Figure (2) shows the equilibrium state of the system after the stopcock separating the two compartments is opened. Assuming the

oxygen and the chlorine behave as ideal gases, what are the signs (+, -, or 0) of H, S, and

G for this process?

Page 18: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

A. H =

+, S =

-, G = +

   

B. H =

0, S =

+, G = -

100%    

C. H =

0, S =

-, G = +

   

D. H = -,

S = +,

G = -

   

Score: 1/1

 

5. Question 081 

If G is small and positive,

 Student

ResponseValue Correct Answer Feedback

A. the forward reaction is spontaneous and the system is far

   

Page 19: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

from equilibrium.

B. the forward reaction is spontaneous and the system is near equilibrium.

   

C. the reverse reaction is spontaneous and the system is far from equilibrium.

   

D. the reverse reaction is spontaneous and the system is near equilibrium.

100%    

Score: 1/1

 

6. Question 071  If Q increases

 Student

ResponseValue Correct Answer Feedback

A. G

increases and the reaction becomes more spontaneous.

   

B. G

increases and the reaction becomes less

100%    

Page 20: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

spontaneous.C.

G decreases and the reaction becomes more spontaneous.

   

D. G

decreases and the reaction becomes less spontaneous.

   

Score: 0.34/0.34

 

7. Question 069

 

G = G for a reaction

 Student

ResponseValue Correct Answer Feedback

A. if Q = K.    B. if Q = 1. 100%    C. at STP.    D. at the start

of the reaction.

   

Score: 0.34/0.34

 

8. Question 040  During perspiration,

 Student

ResponseValue Correct Answer Feedback

A. the entropy of the water

   

Page 21: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

evaporated decreases and the entropy of the body decreases.

B. the entropy of the water evaporated decreases and the entropy of the body increases.

   

C. the entropy of the water evaporated increases and the entropy of the body decreases.

100%    

D. the entropy of the water evaporated increases and the entropy of the body increases.

   

Score: 0.34/0.34

 

9. Question 026  Under which of the following conditions would one mole of Ne have the highest entropy, S?

 Student

ResponseValue Correct Answer Feedback

A. 27 C and 25 L

   

Page 22: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

B. 137 C and 25 L

   

C. 27 C and 35 L

   

D. 137 C and 35 L

100%    

Score: 0.5/0.5

 

10.

Question 030

 

Which should have the highest standard molar entropy at 25 C?

 Student

ResponseValue Correct Answer Feedback

A. Al(s)    B. Al(l)    C. Al(g) 100%    D. All three

should have a standard molar entropy of zero.

   

Score: 0.5/0.5

 

11.

Question 041

  A hot penny is dropped into cold water inside a polystyrene foam cup. Assuming negligible heat loss to the atmosphere and the cup,

 Student

ResponseValue Correct Answer Feedback

A. the decrease in entropy

0%    

Page 23: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

of the penny is equal to the increase in entropy of the water.

| Spenny

| = | Swater |

B. the decrease in entropy of the penny is less than the increase in entropy of the water.

| Spenny

| < | Swater |

   

C. the decrease in entropy of the penny is more than the increase in entropy of the water.

| Spenny

| > | Swater |

   

D. the entropy of both the penny and the water

   

Page 24: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

increases.

Score: 0/1

 

12.

Question 105

 

What is the entropy change associated with the expansion of one mole of an ideal gas from an initial volume of V to a final volume of 6.50V at constant temperature?

 Student

ResponseValue Correct Answer Feedback

A. S = -

6.50 R ln (Vf/Vi)

   

B. S = R

ln 6.50

100%    

C. S =

6.50 R ln (Vf/Vi)

   

D. S = -

R ln 6.50

   

Score: 1/1

 

13.

Question 099

  Consider the following gas-phase reaction of A2 (shaded spheres) and B2 (unshaded spheres):

Which of the above reaction mixtures is G of reaction = G ?

Page 25: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

A. (1)    B. (2)    C. (3) 100%    D. (4)    

Score: 1/1

 

Title: Chapter 15 new quizStarted: March 7, 2010 2:39 PMSubmitted: March 7, 2010 3:01 PMTime spent: 00:21:29

Total score: 8.5/10 = 85% Total score adjusted by 0.0 Maximum possible score: 10

1.

 

Consider the following generic weak acid reaction.

HA + H2O <==> H3O+ + A -

If a 0.0031M solution of HA has a pH of 3.08, calculate Ka for the acid HA.

Enter your answer with two sig figs in the form: 2.3E-6 for 2.3 x 10-4

  Student Response Value Correct AnswerAnswer: 3.1E-4   100% 3.1E-4 (3.1 × 10-4)

Score: 1.5/1.5

 

2.

 

Ka = 2.0 x 10-9 for HOBr. Calculate the pH of a 0.1171M HOBr solution. Round the pH to two decimal places.

  Student Response Value Correct AnswerAnswer: 4.82   100% 4.82

Score: 1.5/1.5

 

3.

Page 26: CHM1046 Quizzes

 

Calculate the pH of a 2.38 x 10-4 M hydrazine solution. Show your answer to two decimal places and use Kb = 8.9 x 10-7.

  Student Response Value Correct AnswerAnswer: 9.16   100% 9.16

Score: 1.5/1.5

 

4.

 

Hypochlorous acid, HOCl, is a weak acid with a Ka of 3.50x10-8. What is the pH of a 0.38M solution of KOCl? Use two decimal places in your answer.

  Student Response Value Correct AnswerAnswer: 3.94   0% 10.52

Score: 0/1.5

 

5.

 

Refer to Appendix C, Tables C.1 and C.3 to decide which of the following salt solutions will produce a basic solution? You may select more than one answer.

 Student

ResponseValue Correct Answer Feedback

A. C5H5NHBr    B. KI    C. LiOBr 50%    

D. NaCH3CO2 50%    E. NH4Cl    

Score: 2/2

 

6.  Refer to Appendix C, Tables C.1 and C.3 to decide which of the following salt solutions will

produce a acidic solution? You may select more than one answer.

 Student

ResponseValue Correct Answer Feedback

A. LiOBr    

Page 27: CHM1046 Quizzes

 Student

ResponseValue Correct Answer Feedback

B. NaCH3CO2    C. NH4Cl 50%    

D. C5H5NHBr 50%    E. KI    

Score: 2/2

 


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