Name _

Chemical Formulasand Chemical Compounds

Class _ Date

Chapter 7Test

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DIRECTIONS: Write on the line at the right of each statement the letter preceding the word or expression that bestcompletes the statement.

1. The result of changing a subscript in a correctly written chemical formula is to (a) change thenumber of moles represented by the formula; (b) change the charges on the other ions in thecompound; (c) change the formula so that it no longer represents the compound it hadrepresented; (d) have no effect on the formula.

2. The formula for carbon dioxide, COz, can represent (a) one molecule of carbon dioxide; (b) onemole of carbon dioxide molecules; (c) one molar mass of carbon dioxide; (d) all of the above.

3. The correct name for the Hg~+ ion is (a)mercury(I); (b) dimercury(I); (c) mercury(II); (d)dimercury(II).

4. Under the new system of nomenclature, stannic phosphate, Sn3(P04)4, would be called(a) stannous phosphate; (b) tin (IV) phosphate; (c) tin(III) phosphate; (d) tin(II) phosphate.

5. Name the acid with the formula HN03. (a) nitrous acid (b) nitric acid (c) hydro nitrous acid(d) acid trioxide

6. Identify the common acid among the following compounds. (a) ZnCIz (b) CC4 (c) HCI (d) NaCI

7. What is the oxidation number of oxygen in peroxides? (a) - 2 (b) -1 (c) 0 (d) +2

8. In a polyatomic ion, the algebraic sum of the oxidation numbers of all atoms is equal to(a) 0; (b) the number of atoms in the ion; (c) 10; (d) the charge of the ion.

9. What is the oxidation number of magnesium in MgO? (a) -1 (b) 0 (c) + 1 (d) +2

10. What is the oxidation number of sulfur in SOz? (a) 0 (b) + 1 (c) +2 (d) +4

11. The sum of the atomic masses of all the atoms in a formula for a compound would mostproperly be called the (a) molecular mass; (b) formula mass; (c) atomic mass; (d) actual mass.

12. The molar mass of C5z is 76.13 g. How many grams of C5z are present in 10.00 mol?(a) 0.13 g (b) 7.6 g (c) 10 g (d) 761.3 g

13. How many moles of CI03 are present in 0.5 moles of KCI03? (a) 0.5 (b) 1 (c) 1.5 (d) 2

14. The simplest formula may not represent the actual composition of a unit of a(n) (a) ioniccompound; (b) molecular compound; (c) salt; (d) crystal.

15. Knowing the simplest formula and the formula mass of a compound permits the determinationof the compound's (a) molecular formula; (b) bond energy; (c) lattice structure; (d) toxicity.

DIRECTIONS: Write the formulas to the following compounds on the lines provided.

16. compound formed between calcium and chlorine 16

17. compound formed between lead(1I) ions and chromate ions 17

18. aluminum sulfate 18

19. silicon dioxide 19

20. carbon tetraiodide 20

DIRECTIONS: Write the names to the following compounds on the lines provided. Use either the Stock system orprefixes as indicated.

21. Zn3(P04h, prefixes 21

22. Fe(NOzh, Stock system 22

23. NZ04, prefixes 23

24. S03, prefixes 24

25. CC4, Stock system 25

Chemical Formulas and Chemical CompoundsHRW material copyrighted under notice appearing earlier in this warle

Chapter 7 33

DIRECTIONS: Write the answer to questions 26-37 on the line to the right, and show your work in the spaceprovided. Questions 26-37 refer to the following table.

TABLE OF ATOMIC MASSES

Element

SymbolAtomic

Mass (u)Copper

Cu63.546

Chlorine

CI35.453

Nitrogen

N14.0067

Hydrogen

H1.007 94

Sulfur

S32.06

Oxygen

015.9994

Carbon

C12.0111

Chromium

Cr51.996

Lead

Pb207.2

Aluminum

AI26.981 54

Magnesium

Mg24.305

Sodium

Na22.989 77

Fluorine

F18.998 403

Lithium

Li6.941

Bromine

Br79.90426. What is the formula mass of magnesium

chloride, MgCh?

27. What is the molar mass of tetraethyllead,Pb(C2Hs)4?

28. What is the formula mass of cr;;'per(II)chloride, CuCh?

29. What is the percent composition of CuCh?

30. What is the percent composition of CO?

31. What is the percent composition of CF4?

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32. What is the simplest formula of a compound containing 259.2 g of F and 40.8 g of C?

33. What is the simplest formula of a compound that is 7.9% Li and 92.1 % Sr?

34. A compound has the simplest formula CH. If the formula mass is 26 u, what is the molecularformula?

35. A compound with the simplest formula N20S has a formula mass of 108 u. What is themolecular formula?

36. A compound's simplest formula is C2Hs. If the formula mass is 58 u, what is the molecularformula?

37. A compound is found to be 80% carbon and 20% hydrogen. If the formula mass is 30 u, whatis the molecular formula?

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34 Chapter 7 Chemical Formulas and Chemical CompoundsHRW material copyrighted under notice appearing earlier in this work.

Name _

Chemical Equationsand Reactions

Class Date

Chapter 8Test

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DIRECTIONS: Write on the line at the right of each statement the letter preceding the word or expression that bestcompletes the statement.

1. A small whole number that appears in front of a formula in a chemical equation is called a(a) subscript; (b) superscript; (c) ratio; (d) coefficient.

2. According to the law of conservation of mass, the total mass of the reacting substances is(a) always more than the total mass of the products; (b) always less than the total mass of theproducts; (c) sometimes more and sometimes less than the total mass of the products;(d) always equal to the total mass of the products.

3. In a chemical equation, the symbol "(aq)" indicates that the substance is (a) water;(b) dissolved in water; (c) an acid; (d) insoluble.

4. In a chemical equation, the symbol "(t)" indicates that the substance is (a) lighter than air;(b) a liquid; (c) lost in the reaction; (d) luminous.

5. For the equation 2Mg + O2 -+ 2MgO, the word equation would begin (a) manganese plusoxygen; (b) molybdenum plus oxygen; (c) magnesium plus oxygen; (d) heat plus oxygen.

6. A chemical formula written over the arrow in a chemical equation signifies (a) a byproduct;(b) the formation of a gas; (c) a catalyst for the reaction; (d) an impurity.

7. What is the ratio of chlorine to hydrogen chloride in the reaction H2(g) + Ch(g) -> 2HCl(g)?(a) 1:1 (b) 1:2 (c) 2:1 (d) 2:2

8. The equation AX + BY-'> AY + BX is the general equation for a (a) synthesis reaction;(b) decomposition reaction; (c) single-replacement reaction; (d) double-replacement reaction.

9. A reaction in which a single compound produces two or more simpler substances is calleda(n) (a) decomposition reaction; (b) synthesis reaction; (c) single-replacement reaction;(d) ionic reaction.

10. Oxides of active metals, such as CaO, react with water to produce (a) metal carbonates;(b) metal hydrides; (c) acids; (d) metal hydroxides.

11. The production of a slightly soluble solid compound in a double replacement reaction resultsin the formation of a (a) gas; (b) precipitate; (c) combustion reaction; (d) halogen.

12. The activity series of metals is based on the ease with which metal (a) atoms gain neutrons;(b) nuclei fuse; (c) atoms form covalent bonds; (d) atoms lose electrons.

13. The tendency for a replacement reaction to occur increases as the (a) interval between any twoelements in the activity series decreases; (b) temperature decreases; (c) valence electrons areused up; (d) interval between any two elements in the activity series increases.

14. Calcium, near the top of the activity series, will (a) not react with oxygen; (b) react rapidly withoxygen to form an oxide; (c) react only indirectly to form an oxide; (d) react slowly with oxygento form an oxide.

15. When heated with hydrogen, oxides of metals above iron in the activity series (a) quickly yieldmetals; (b) form hydroxides; (c) resist conversion to free metals; (d) form metal hydrides.

DIRECTIONS: Balance the following equations in the space provided.

16. AgN03 + CuCh -'> AgCl + Cu(N03h 16

17. C + O2 -> CO 17

Chemical Equations and ReactionsHRW material copyrighted under notice appearing earlier in this worK,

Chapter 8 37

18. Ah(S04b + Ca(OHh -> CaS04 + AI(OHb

19. Hz + Oz -> HzO

20. KCI03 -> KCl + Oz

DIRECTIONS: Write on the line at the right either synthesis, decomposition, single-replacement, or

double-replacement, depending on the type of reaction on the left.

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21. 2Mg(s) + Oz(g) -> 2MgO(s) ~___ 21

22. Mg(s) + 2HCI(aq) -> MgCh(aq) + Hz(g)

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23. 2HgO(s) ---? 2Hg(e) + Oz(g)

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24. Pb(N03h(aq) + 2KI(aq) -> Pbh(s) + 2KN03(aq)

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25. CaO(s) + S03(g) -> CaS04(s)

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26. Ch(g) + 2KBr(aq) ---? 2KCl(aq) + Brz(e)

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27. Zn(s) + CuS04(aq) ---? ZnS04(aq) + Cu(s)

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28. HzO(e)+ S03(g) ---? HZS04(aq)

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29. (NH4hC03(S) ---? 2NH3(g) + HzO(g) + CO2(g)

29"-.J

30. NaCI(aq) + AgN03(aq) -> NaN03(aq) + AgCI(s)

30

DIRECTIONS: Write the products of the reaction on the left on the lines provided.

31. decomposition of magnesium hydroxide 31

32. decomposition of sodium chlorate 32

33. reaction between calcium and hydrochloric acid 33

34. reaction between sodium hydroxide and sulfuric acid 34

35. decomposition of barium carbonate 35

DIRECTIONS: Write on the lines provided whether or not the addition of the substances on the left will induce areaction. If a reaction will occur, write the products.

36. addition of zinc metal to water 36

37. addition of zinc metal to hydrochloric acid 37

38. addition of chlorine gas to a solution of magnesium bromide 38

39. addition of chlorine gas to hydrofluoric acid 39

40. addition of potassium to water 40

38 Chapter 8 Chemical Equations and ReactionsHRW material copyrighted under notice appearing earlier in this work.