CHM 2045C Module 5 Sample Exam

 

Module Five Part M: Multiple Choice Chapters 2, 3, 4 10 points

 

____1. Which of the following is equal to one mole of substance?

(A) 6.02 x 1023 sodium atoms, Na

(B) 6.02 x 1023 chlorine molecules, Cl2

(C) 6.02 x 1023 sodium chloride formula units, NaCl

(D) 6.02 x 1023 chloride ions, Cl 1-

(E) A & B are both correct

(F) C & D are both correct

(G) all of the above are correct

 

____2. Which of the following represents 1 mole of ozone gas, O3?

(A) 6.02 x 1023 ozone molecules

(B) 48.0 g ozone gas

(C) 22.4 L ozone gas at STP

(D) all of the above

(E) none of the above

 

_____3. What is the molecular mass of mercurous nitrate, Hg2(NO3)2 ?

(A) 463.2 g/mol

(B) 477.2 g/mol

(C) 511.2 g/mol

(D) 525.2 g/mol

(E) 649.2 g/mol

(F) none of the above

 

_____4. If 0.125 mol of S combines with 0.250 mol of O, what is the empirical formula of sulfur oxide?

(A) SO

(B) SO2

(C) SO4

(D) S2O

(D) S4O

 

_____ 5. The insulating material Styrofoam is a polymer of styrene. Find the molecular formula of styrene given its percentage composition:

92.25% Carbon, 7.75% hydrogen.

The approximate molar mass is 104 g/mol.

(A) C1H1

(B) C1H8

(C) C1H12

(D) C8H8

(E) C9H7


(F) C12H1

 

 

 

_____6. What is the term that expresses the simplest whole number ratio of atoms in a molecule, or ions in a formula unit?

(A) chemical formula

(B) simplest formula

(C) molecular formula

(D) empirical formula

(E) mass ratio composition

(F) percentage composition

 

_____7. Which of the following is evidence for a chemical reaction?

(A) a gas is detected

(B) a precipitate is formed

(C) a color change is observed

(D) an energy change is noted

(E) both B & C are correct

(F) all are correct

(G) none of the above

 

_____8. What is the term for a compound that releases hydrogen ions when dissolved in water?

(A) acid

(B) aqueous acid

(C) base

(D) aqueous base

(E) none of the above

 

______9. The product(s) of a neutralization reaction is (are)

(A) water

(B) aqueous acid

(C) aqueous base

(D) salt

(E) aqueous acid and aqueous base

(F) aqueous acid and water

(G) salt and water

(H) aqueous base and water

(I) aqueous acid, water, aqueous base

(J) none of the above

 

______10. Ethane, C2H6, burns to give carbon dioxide and water. What is the coefficient of oxygen gas need to balance the reaction:

(A) 5

(B) 7

(C) 10

(D) 14

(E) none of the above


 

 

11. ___ H2SnCl6 + ___ H2S --> ___ SnS2 + ___ HCl
When the equation above is properly balanced with the smallest whole numbers, the respective coefficients are:

a.

1, 2, 1, 6

b.

1, 1, 1, 3

c.

2, 4, 2, 6

d.

2, 4, 2, 12

e.

1, 4, 2, 6

 

12. The products of the combustion of propionaldehyde with oxygen are shown in the following equation:

___ CH3CH2CHO + ___ O2 --> ___ CO2 + ___ H2O

When properly balanced, the equation indicates that ___ mol of O2 are required for each mol of CH3CH2CHO.

a.

3

b.

3.5

c.

4

d.

4.5

e.

5

 

13. Carbon dioxide, CO2, and ammonia, NH3, combine to form urea, CH4ON2, plus water. Write a balanced equation and calculate the mass of ammonia in grams that would be needed to make two moles of urea.

a.

25 to 35 g

b.

35 to 45 g

c.

50 to 60 g

d.

60 to 70 g

e.

75 to 85 g

 

14. Calculate the mass of hydrogen formed when 25 g of aluminum react with excess hydrochloric acid.
2Al + 6HCl --> 2AlCl3 + 3H2

a.

0.41 g

b.

0.92 g

c.

1.2 g

d.

1.8 g

e.

2.8 g

15. When 8.00 grams of hydrogen gas react with 32.0 grams of oxygen gas in an explosion, the final gas mixture will contain:

a.

H2, H2O, and O2

b.

H2, H2O

c.

O2, H2O

d.

H2, O2

e.

Pure H2O

 

16. How many g of nitric acid can be prepared from the reaction of 92.0 of nitrogen dioxide with 36.0 g of water?
3NO2 + H2O --> 2HNO3 + NO

a.

64

b.

76

c.

84

d.

116

e.

252

 

17. Sulfur trioxide, SO3, is made from oxidation of SO2, which is represented by the equation:

2SO2 + O2 --> 2SO3

A 16.0 g sample of SO2 gives 18.0 g of SO3. The percent yield of SO3 is

a.

60%.

b.

75%.

c.

80%.

d.

90%.

e.

100%.

 

18. When CaSO4y H2O is heated, all of the water is driven off. If 34.0 g of CaSO4

(FW = 136) is formed from 43.0 g of CaSO4y H2O, what is the value of y?

a.

1

b.

2

c.

3

d.

4

e.

5

 

 

 

 

19. A 27.0 g sample of an unknown carbon-hydrogen compound was burned in excess oxygen to form 88.0 g of CO2 and 27.0 g H2O. What is a possible molecular formula of the hydrocarbon?

a.

CH4

b.

C2H6

c.

C4H6

d.

C4H8

e.

C4H10

 

20. A 1.183 g sample of metal carbonate was heated to give the metal oxide and 0.617 g CO2.

MCO3(s) --> MO(s) + CO2(g)

What is the identity of the metal (assume the metal has a charge of 2+ and the above equation is balanced)?

a.

Fe

b.

Mn

c.

Zn

d.

Ba

e.

Mg

 

Use the following choice in questions 21-25 to classify each of the following chemical equations (unbalanced):

A. Combination (or synthesis)

B. Decomposition (or analysis)

C. Single replacement

D. Double Replacement (Precipitation)

E. Neutralization

F. Combustion with Oxygen

 

_____21. C5H12 + O2 CO2 + H2O

 

_____22. K + S K2S

 

_____23. Al(OH)3 + HNO3 Al(NO3)3 + H2O

 

_____24. Zn + HCl ZnCl2 + H2

 

_____25. KClO3 KCl + O2

 

Answers:

1.g 2. d 3. d 4. b 5. d 6.d 7.f 8.b 9.g 10.b

11.a 12.c 13.d 14.e 15.b 16.c 17.d 18.b 19. c 20.e

21. f 22. a 23. e 24.c 25.b