General Chemistry

1. A 5.00 g sample of a brownie with nuts is burned in a bomb calorimeter containing 2025 g of water. The temperature of the water increases from 23.50C to 33.47C. How much heat, in joules, did the brownie release when it burned? (Cwater = 4.184 J/gC)

A) 1.99  105 J D) 8.45  104 J

B) 2.80  105 J E) 7.00  102 J

C) 4.92  102 J

2. Which of the following compounds is a ketone?

A) CH3CH2OH D) CH3CH2COCH3

B) CH3CH2CO2H E) CH3CHO

C) CH3OCH3

3. Iron metal reacts with hydrochloric acid as follows:

2Fe(s) + 6HCl(aq)  2FeCl3(aq) + 3H2(g)

If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl3 are collected, what is the percent yield of the reaction?

A) 65.0% B) 109% C) 91.4% D) 73.0% E) not enough information given

4. In the process of obtaining lead from PbS, or galena, the galena is “roasted” (heated in the presence of oxygen), so that the following reaction occurs:

2PbS(s) + 3O2(g)  2PbO(s) + 2SO2(g)

If 50.0 g of PbS reacts with 25.0 g of oxygen, how many grams of PbO will be formed?

A) 116 g B) 46.6 g C) 163 g D) 69.9 g E) 93.2 g

5. Phosphorus trichloride can be made by the reaction:

P4(s) + 6Cl2(g)  4PCl3(l)

What is the maximum amount of phosphorus trichloride that can be formed if 10 molecules of P4 react with 36 molecules of chlorine?

A) 4 molecules D) 24 molecules

B) 6 molecules E) 46 molecules

C) 12 molecules

6. Consider the reaction:

Zn(s) + NO3(aq)  NH3(aq) + Zn(OH)42(aq)

When this equation is balanced in basic solution, the coefficient for water will be__________, and the number of electrons transferred will be __________.

A) 3, 3 B) 2, 1 C) 6, 8 D) 5, 6 E) 2, 3

7. If the pH of a blood sample is 7.60, what is the H3O+ concentration in the blood?

A) 7.6 M B) 2.5  108 M C) 2.5  107 M D) 2.5  109 M E) 6.4 M

8. If CH3NH2 is added to water, what other compound could also be added in order to make a buffered solution?

A) H2O D) NaCH3NH2

B) NaOH E) none of these is correct

C) CH3NH3Cl

9. What is the pH of a 0.015 M NaOH solution?

A) 0.015 B) 1.82 C) 7.00 D) 12.18 E) –1.82

10. Ethane, C2H6, can be formed by reacting acetylene, C2H2, with hydrogen gas as follows:

C2H2(g) + H2(g) image1.png C2H6(g) Exothermic

What change will be observed if the temperature of the reaction mixture at equilibrium were increased?

A) The concentration of C2H6 will increase.

B) The concentration of both C2H2 and H2 will increase.

C) The concentration of both C2H2 and H2 will decrease.

D) The concentration of H2 only will decrease.

E) There will be no change in the equilibrium concentrations.

11. Consider the following reaction:

N2O4(g) image2.png 2NO2(g) q = +58.2 kJ

What will cause an increase in the concentration of NO2 at equilibrium?

A) The NO2 concentration can never change because the reaction is at equilibrium.

B) an increase in temperature

C) an increase in pressure

D) a decrease in volume

E) adding a catalyst

12. Which of the following compounds is an aldehyde?

A) CH3CH2OH D) CH3COCH3

B) CH3CH2COCH3 E) CH3CHO

C) CH3OCH3

13. Which one of the following reactions is an example of an oxidation-reduction reaction?

A) BaO(s) + CO2(g)  BaCO3(s)

B) H2(g) + F2(g)  2HF(g)

C) CaCO3(s)  CaO(s) + CO2(g)

D) HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)

E) Ba2+(aq) + SO42–(aq)  BaSO4(s)

14. Consider the following reaction:

Mn(s) + CuSO4(aq)  MnSO4(aq) + Cu(s)

Which of the following statements regarding this reaction is correct?

A) Manganese is neither oxidized nor reduced.

B) The sulfate ion is oxidized.

C) Copper is the reducing agent.

D) Manganese is the oxidizing agent.

E) Each copper gains two electrons.