A. the Reaction Releases Energy

Predicting Products

1. The word equation solid carbon + oxygen gas ® carbon dioxide gas + energy, represents a chemical reaction because

a. the reaction releases energy.

b. CO2 has chemical properties that differ from those of C and O.

c. the reaction absorbs energy.

d. CO2 is a gas and carbon is a crystal.

2. To balance a chemical equation, it may be necessary to adjust the

a. coefficients. c. formulas of the products.

b. subscripts. d. number of products.

3. In the chemical equation 2Mg(s) + O2(g) ? 2MgO(s),

a. Mg represents the product magnesium. c. Mg represents the reagent magnesium.

b. the reaction yields magnesium. d. O2 represents the product oxygen gas.

4. In an equation, the symbol for a substance in water solution is followed by

a. (1). b. (g). c. (aq). d. (s).

5. A chemical formula written over the arrow in a chemical equation signifies

a. a by-product. c. a catalyst for the reaction.

b. the formation of a gas. d. an impurity.

6. Which coefficients correctly balance the formula equation CaO + H2O ® Ca(OH)2?

a. 2, 1, 2 b. 1, 2, 3 c. 1, 2, 1 d. 1, 1, 1

7. What is the balanced equation for the combustion of sulfur?

a. S(s) + O2(g) ® SO(g) c. 2S(s) + 3O2(g) ® SO3(s)

b. S(s) + O2(g) ® SO2(g) d. S(s) + 2O2(g) ® SO42–(aq)

8. In what kind of reaction do two or more substances combine to form a new compound?

a. decomposition reaction c. double-displacement reaction

b. ionic reaction d. synthesis reaction

9. In what kind of reaction does one element replace a similar element in a compound?

a. displacement reaction c. decomposition reaction

b. combustion d. ionic reaction

10. In what kind of reaction does a single compound produce two or more simpler substances?

a. decomposition reaction c. single-displacement reaction

b. synthesis reaction d. ionic reaction

11. In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds?

a. synthesis reaction c. decomposition reaction

b. double-displacement reaction d. combustion reaction

12. The reaction represented by the equation 2KClO3(s) ® 2KCl(s) + 3O2(g) is a(n)

a. synthesis reaction. c. combustion reaction.

b. decomposition reaction. d. ionic reaction.

13. The reaction represented by the equation Cl2(g) + 2KBr(aq) ® 2KCl(aq) + Br2(l) is a(n)

a. synthesis reaction. c. single-displacement reaction.

b. decomposition reaction. d. combustion reaction.

14. In one type of synthesis reaction, an element combines with oxygen to yield a(n)

a. acid. c. oxide.

b. hydroxide. d. metal.

15. The decomposition of a substance by an electric current is called

a. electrolysis. c. ionization.

b. conduction. d. transformation.

16. When heated, a metal carbonate decomposes into a metal oxide and

a. carbon. c. oxygen.

b. carbon dioxide. d. hydrogen.

17. Oxides of active metals, such as CaO, react with water to produce

a. metal carbonates. c. acids.

b. metal hydrides. d. metal hydroxides.

18. An active metal and a halogen react to form a(n)

a. salt. c. acid.

b. hydroxide. d. oxide.

19. When a binary compound decomposes, what is produced?

a. an oxide c. a tertiary compound

b. an acid d. two elements

20. Many metal hydroxides decompose when heated to yield metal oxides and

a. metal hydrides. c. carbon dioxide.

b. water. d. an acid.

21. When a metal chlorate is heated, it decomposes to yield a metal chloride and

a. a metal oxide. c. hydrogen.

b. a metal hydroxide. d. oxygen.

22. Some acids, such as carbonic acid, decompose to nonmetal oxides and

a. water. b. a salt. c. oxygen. d. peroxide.

23. When heated, metallic chlorates decompose into

a. metallic oxides and chlorine.

b. metallic chlorides and oxygen.

c. a metal and a compound of chlorine and oxygen.

d. a metal, chlorine, and oxygen.

24. In the equation 2Al(s) + 3Fe(NO3)2(aq) ® 3Fe(s) + 2Al(NO3)3(aq), iron has been replaced by

a. nitrate. b. water. c. aluminum. d. nitrogen.

25. Group 1 metals react with water to produce metal hydroxides and

a. metal hydroxides. c. oxygen.

b. hydrochloric acid. d. hydrogen.

26. The replacement of bromine by chlorine in a salt is an example of a single-displacement reaction by

a. halogens. c. water.

b. sodium. d. electrolysis.

27. An insoluble gas that forms in a double-displacement reaction in aqueous solution

a. bubbles out of solution. c. disassociates into ions.

b. forms a precipitate. d. reacts with the water.

28. In a double-displacement reaction, hydrogen chloride and sodium hydroxide react to produce sodium chloride. Another product is

a. sodium hydride. c. water.

b. potassium chloride. d. hydrogen gas.

29. Active metals react with certain acids, such as hydrochloric acid, to yield a metal compound and

a. oxygen. c. chlorine.

b. hydrogen. d. sodium.

30. Some metals, such as iron, react with steam to produce hydrogen gas and a

a. metal hydroxide. c. metallic acid.

b. metal hydride. d. metal oxide.

31. When potassium reacts with water, one product formed is

a. hydrogen gas. c. potassium oxide.

b. oxygen gas. d. salt.

32. The reaction of calcium oxide, CaO, with water yields

a. calcium and oxygen gas. c. calcium and a salt.

b. calcium hydroxide. d. carbon dioxide and water.

33. Predict the product of the reaction represented by the following equation:

MgO + CO2 ®

a. MgCO3 c. MgC + O3

b. Mg + CO3 d. MgCO2 + O

34. Magnesium hydroxide decomposes to yield magnesium oxide and

a. hydrogen. c. water.

b. oxygen. d. salt.

35. When sodium chlorate, NaClO3, decomposes, the products are

a. sodium hydroxide and water. c. sodium and chlorine oxide.

b. sodium oxide and chlorine. d. sodium chloride and oxygen.

36. If chlorine gas is produced by halogen replacement, the other halogen in the reaction must be

a. bromine. c. astatine.

b. iodine. d. fluorine.

37. The formulas for the products of the reaction between sodium hydroxide and sulfuric acid are

a. Na2SO4 and H2O. c. SI4 and Na2O.

b. NaSO4 and H2O. d. S + O2 and Na.

38. What is the name of a list of elements arranged according to the ease with which they undergo certain chemical reactions?

a. reactivity list c. activity series

b. reaction sequence d. periodic list

39. An element in the activity series can replace any element

a. in the periodic table. c. above it on the list.

b. below it on the list. d. in its group.

40. If metal X is lower than metal Y in the activity series, then metal X

a. replaces ions of metal Y in a solution.

b. loses electrons more readily than does metal Y.

c. loses electrons less readily than does metal Y.

d. forms positive ions more readily than does metal Y.

41. Predict what happens when calcium metal is added to a solution of magnesium chloride.

a. No reaction occurs. c. Magnesium calcite forms.

b. Calcium chloride forms. d. Gaseous calcium is produced.

42. Predict what happens when zinc is added to water.

a. No reaction occurs. c. Zinc oxide forms.

b. Steam is produced. d. Hydrogen is released.

43. Magnesium bromide (aq) + chlorine (g) yields

a. Mg(s) and BrCl(aq). c. MgBrCl(aq).

b. MgCl(aq) and Br2(l). d. MgCl2(aq) and Br2(l).

44. Which reaction does not occur?

a. 2HF(aq) + Cl2(g) ® F2(g) + 2HCl(aq)

b. 2Na(s) + ZnF2(aq) ® 2NaF(aq) + Zn(s)

c. Fe(s) + CuCl2(aq) ® FeCl2(aq) + Cu(s)

d. 2HCl(aq) + Mg(s) ® MgCl2(aq) + H2(g)

45. Which reaction can be predicted from the activity series?

a. 2Cl(g) ® Cl2(g)

b. HCl(aq) + NaOH(aq) ® NaCl(aq) + H2O(l)

c. 2H2O(aq) + 2Na(s) ® 2NaOH(aq) + H2(g)

d. Cl2(g) ® 2Cl(g)