Holt: Modern Chemistry

Mickey Sarquis, Jerry L. Sarquis

Chapter 7

Chemical Formulas AND CHEMICAL COMPOUNDS - all with Video Answers

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Chapter Questions

Problem 1

a. What are monatomic ions?
b. Give three examples of monatomic ions.

Sarah Bennett

Sarah Bennett

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Problem 2

How does the chemical formula for the nitrite ion differ from the chemical formula for the nitrate ion?

Sarah Bennett

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Problem 3

Using only the periodic table, write the symbol of the ion most typically formed by each of the following
elements:
a. K d. Cl
b. Ca e. Ba
c. S f. Br

Jennifer Hudspeth

Jennifer Hudspeth

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Problem 4

Write the formula for and indicate the charge on each of the following ions:
a. sodium ion
b. aluminum ion
c. chloride ion
d. nitride ion
e. iron(II) ion
f. iron(III) ion

Sarah Bennett

Numerade Educator

Problem 5

Name each of the following monatomic ions:
a. ${K}^{+}$ d. ${Cl}^{-}$
b. Mg $^{2+}$ e. ${O}^{2-}$
c. ${Al}^{3+}$ f. ${Ca}^{2+}$

Sarah Bennett

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Problem 6

Write formulas for the binary ionic compounds formed between the following elements. (Hint: See Sample Problem A.)
a. sodium and iodine
b. calcium and sulfur
c. zinc and chlorine
d. barium and fluorine
e. lithium and oxygen

Natalie Britton

Natalie Britton

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Problem 7

Give the name of each of the following binary ionic compounds. (Hint: See Sample Problem B.)
a) ${KCl}$ c) ${Li}_{2} {O}$
b) ${CaBr}_{2}$ d) ${MgCl}_{2}$

Sarah Bennett

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Problem 8

Write the formulas for and give the names of the compounds formed by the following ions:
a. ${Cr}^{2+}$ and ${F}^{-}$
b. ${Ni}^{2+}$ and ${O}^{2-}$
c. ${Fe}^{3+}$ and ${O}^{2-}$

Sarah Bennett

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Problem 9

What determines the order in which the component elements of binary molecular compounds are
written?

Sarah Bennett

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Problem 10

Name the following binary molecular compounds according to the prefix system. (Hint: See Sample
Problem D.)
a) ${CO}_{2}$ d) ${SeF}_{6}$
b) ${CCl}_{4}$ e) ${As}_{2} {O}_{5}$
c) ${PCl}_{5}$

Sarah Bennett

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Problem 11

Write formulas for each of the following binary molecular compounds. (Hint: See Sample Problem D.)
a. carbon tetrabromide
b. silicon dioxide
c. tetraphosphorus decoxide
d. diarsenic trisulfide

Sarah Bennett

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Problem 12

Distinguish between binary acids and oxyacids, and give two examples of each.

Sarah Bennett

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Problem 13

a. What is a salt?
b. Give two examples of salts.

Sarah Bennett

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Problem 14

Name each of the following acids:
a) ${HF}$ d) ${H}_{2} {SO}_{4}$
b) ${HBr}$ e) ${H}_{3} {PO}_{4}$
c) ${HNO}_{3}$

Sarah Bennett

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Problem 15

Give the molecular formula for each of the following acids:
a. sulfurous acid
b. chloric acid
c. hydrochloric acid
d. hypochlorous acid
e. perchloric acid
f. carbonic acid
g. acetic acid

Sarah Bennett

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Problem 16

Write formulas for each of the following compounds:
a. sodium fluoride
b. calcium oxide
c. potassium sulfide
d. magnesium chloride
e. aluminum bromide
f. lithium nitride
g. iron(II) oxide

Sarah Bennett

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Problem 17

Name each of the following ions:
a) ${NH}_{4}^{+}$ f) ${CO}_{3}^{2-}$
b) ${ClO}_{4}^{-}$ g) ${PO}_{4}^{3-}$
c) ${OH}^{-}$ h) ${CH}_{3} {COO}^{-}$
d) ${SO}_{4}^{2-}$ i) ${HCO}_{3}^{-}$
e) ${NO}_{3}^{-}$ j) ${CrO}_{4}^{2-}$

Sarah Bennett

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Problem 18

Write the formula and charge for each of the following ions:
a. ammonium ion g. copper(II) ion
b. acetate ion h. tin(II) ion
c. hydroxide ion i. iron(III) ion
d. carbonate ion j. copper(I) ion
e. sulfate ion k. mercury(I) ion
f. phosphate ion l. mercury(II) ion

Dr. Satish Ingale

Dr. Satish Ingale

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Problem 19

Name each of the following ions according to the Stock system:
a. ${Fe}^{2+}$ d. ${Pb}^{4+}$
b.${Fe}^{3+}$ e. ${Sn}^{2+}$
c.${Pb}^{2+}$ f. ${Sn}^{4+}$

Sarah Bennett

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Problem 20

Name each of the binary molecular compounds in item 11 by using the Stock system.

Sarah Bennett

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Problem 21

Write formulas for each of the following compounds:
a. phosphorus(III) iodide
b. sulfur(II) chloride
c. carbon(IV) sulfide
d. nitrogen(V) oxide

Sarah Bennett

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Problem 22

a. What are oxidation numbers?
b. What useful functions do oxidation numbers serve?

Sarah Bennett

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Problem 23

Name each of the following ionic compounds by using the Stock system:
a. NaCl
b. KF
c. CaS
d. ${Co}({NO}_{3})_{2}$
e. FePO,
t. ${Hg}_{2} {SO}_{4}$
g. ${Hg}_{3}({PO}_{4})_{2}$

Sarah Bennett

Numerade Educator

Problem 24

Assign oxidation numbers to each atom in the following compounds. (Hint: See Sample Problem E.)
a. HI
b. ${PBr}_{3}$
c. Ges $_{2}$
d. ${KH}$
e. ${As}_{2} {O}_{5}$
f. ${H}_{3} {PO}_{4}$

Sarah Bennett

Numerade Educator

Problem 25

Assign oxidation numbers to each atom in the following ions. (Hint: See Sample Problem E.)
a) ${NO}_{3}^{-}$
b) ${ClO}_{4}^{-}$
c) ${PO}_{4}^{3-}$
d) ${Cr}_{2} {O}_{7}^{2-}$
e) ${CO}_{3}^{2-}$

Sarah Bennett

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Problem 26

a. Define formula mass.
b. In what unit is formula mass expressed?

Sarah Bennett

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Problem 27

What is meant by the molar mass of a compound?

Sarah Bennett

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Problem 28

Determine the formula mass of each of the following compounds or ions. (Hint: See Sample Problem F.)
a. glucose, $C_{6} {H}_{12} {O}_{6}$
b. calcium acetate, ${Ca}({CH}_{3} {COO})_{2}$
c. the ammonium ion, ${NH}_{4}^{+}$
d. the chlorate ion, ${ClO}_{3}^{-}$

Sarah Bennett

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Problem 29

Determine the number of moles of each type of monatomic or polyatomic ion in one mole of the
following compounds. For each polyatomic ion, determine the number of moles of each atom present
in one mole of the ion.
a. ${KNO}_{3}$
b. ${Na}_{2} {SO}_{4}$
c. ${Ca}({OH})_{2}$
d. $({NH}_{4})_{2} {SO}_{3}$
e. ${Ca}_{3}({PO}_{4})_{2}$
f. ${Al}_{2}({CrO}_{4})_{3}$

Prashant Bana

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Problem 30

Determine the molar mass of each compound listed in item 29. (Hint: See Sample Problem G.)

TF

Travis Fillion

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Problem 31

Determine the number of moles of compound in each of the following samples. (Hint: See Sample
Problem I.)
a) 4.50 ${g} {H}_{2} {O}$
b) 471.6 ${g} {Ba}({OH})_{2}$
c) 129.68 ${g} {Fe}_{3}({PO}_{4})_{2}$

Sarah Bennett

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Problem 32

Determine the percentage composition of each of the following compounds. (Hint: See Sample Problem J.)
a. NaCl
b. ${AgNO}_{3}$
c. ${Mg}({OH})_{2}$

Sarah Bennett

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Problem 33

Determine the percentage by mass of water in the hydrate Cuso $_{4} \cdot 5 {H}_{2} {O}$ . (Hint: See Sample Problem ${K}$ .

Vishal Sharma

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Problem 34

What three types of information are used to find an empirical formula from percentage composition
data?

Scott Moran

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Problem 35

What is the relationship between the empirical formula and the molecular formula of a compound?

Sarah Bennett

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Problem 36

Determine the empirical formula of a compound containing 63.50% silver, 8.25% nitrogen, and 28.25%
oxygen. (Hint: See Sample Problem L.)

Sarah Bennett

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Problem 37

Determine the empirical formula of a compound found to contain 52.11% carbon, 13.14% hydrogen,
and 34.75% oxygen.

Sarah Bennett

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Problem 38

What is the molecular formula of the molecule that has an empirical formula of ${CH}_{2} {O}$ and a molar mass of 120.12 ${g} / {mol}$ ?

Sarah Bennett

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Problem 39

A compound with a formula mass of 42.08 u is found to be 85.64% carbon and 14.36% hydrogen by mass. Find its molecular formula.

Sarah Bennett

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Problem 40

Chemical analysis shows that citric acid contains 37.51% C, 4.20% H, and 58.29% O. What is the
empirical formula for citric acid?

Sarah Bennett

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Problem 41

Name each of the following compounds by using the Stock system:
a) LiBr f) ${Fe}_{2} {O}_{3}$
b) ${Sn}({NO}_{3})_{2}$ g) ${AgNO}_{3}$
c) ${FeCl}_{2}$ h) ${Fe}({OH})_{2}$
d) ${MgO}$ i) ${CrF}_{2}$
e) ${KOH}$

Sarah Bennett

Numerade Educator

Problem 42

What is the mass in grams of each of the following samples?
a. 1.000 ${mol} {NaCl}$
b. 2.000 ${mol} {H}_{2} {O}$
c. 3.500 ${mol} {Ca}({OH})_{2}$
d. 0.625 ${mol} {Ba}({NO}_{3})_{2}$

Sarah Bennett

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Problem 43

Determine the formula mass and molar mass of each of the following compounds:
a) ${XeF}_{4}$
b) ${C}_{12} {H}_{24} {O}_{6}$
c) ${Hg}_{2} {I}_{2}$
d) ${CuCN}$

Sarah Bennett

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Problem 44

Write the chemical formulas for the following compounds:
a. aluminum fluoride
b. magnesium oxide
c. vanadium(V) oxide
d. cobalt(II) sulfide
e. strontium bromide
f. sulfur trioxide

Sarah Bennett

Numerade Educator

Problem 45

How many atoms of each element are contained in a single formula unit of iron(III) formate, Fe $({CHO}_{2})_{3} \cdot {H}_{2} {O}$ ? What percentage by mass of the compound is water?

Sarah Bennett

Numerade Educator

Problem 46

Name each of the following acids, and assign oxidation numbers to the atoms in each:
a. ${HNO}_{2} $ c. ${H}_{2} {CO}_{3}$
b. ${H}_{2} {SO}_{3} $ d. HI

Sarah Bennett

Numerade Educator

Problem 47

Determine the percentage composition of the following compounds:
a. ${NaClO}$ c. $C_{2} {H}_{5} {COOH}$
b. ${H}_{2} {SO}_{3}$ d. ${BeCl}_{2}$

Pam Owens

Numerade Educator

Problem 48

Name each of the following binary compounds:
a) ${Mgl}_{2}$ e) ${SO}_{2}$
b) ${NaF}$ f) ${PBr}_{3}$
c) ${CS}_{2}$ g) ${CaCl}_{2}$
d) ${N}_{2} {O}_{4}$ h) ${Agl}$

Sarah Bennett

Numerade Educator

Problem 49

Assign oxidation numbers to each atom in the following molecules and ions:
a) ${CO}_{2}$ e. ${H}_{2} {O}_{2}$
b) ${NH}_{4}^{+}$ t. ${P}_{4} {O}_{10}$
c) ${MnO}_{4}^{-}$ g. ${OF}_{2}$
d) ${S}_{2} {O}_{3}^{2-}$

Sarah Bennett

Numerade Educator

Problem 50

A 175.0 g sample of a compound contains 56.15 g C, 9.43 g H, 74.81 g O, 13.11 g N, and 21.49 g Na. What is the compound’s empirical formula?

Sarah Bennett

Numerade Educator

Problem 51

Analyzing Information Sulfur trioxide is produced in the atmosphere through a reaction of sulfur dioxide
and oxygen. Sulfur dioxide is a primary air pollutant. Analyze the formula for sulfur trioxide. Then, use
your analysis to list all of the chemical information that you can.

Dr. Satish Ingale

Dr. Satish Ingale

Numerade Educator

Problem 52

Analyzing Data In the laboratory, a sample of pure nickel was placed in a clean, dry, weighed crucible. The crucible was heated so that the nickel would react with the oxygen in the air. After the reaction appeared complete, the crucible was allowed to cool and the mass was determined. The crucible was reheated and allowed to cool. Its mass was then determined again to be certain that the reaction was complete. The following data were collected:
Mass of crucible = 30.02 g
Mass of nickel and crucible = 31.07 g
Mass of nickel oxide and crucible = 31.36 g
Determine the following information based on the data given above:
Mass of nickel =
Mass of nickel oxide =
Mass of oxygen =
Based on your calculations, what is the empirical
formula for the nickel oxide?

Sarah Bennett

Numerade Educator

Problem 53

Review the common reactions of Group 1 metals in the Elements Handbook (Appendix A), and answer
the following questions:
a. Some of the Group 1 metals react with oxygen to form superoxides. Write the formulas for these compounds.
b. What is the charge on each cation for the formulas that you wrote in (a)?
c. How does the charge on the anion vary for oxides, peroxides, and superoxides?

Kaitlynn Wade

Numerade Educator

Problem 54

Review the common reactions of Group 2 metals in the Elements Handbook (Appendix A), and answer the following questions:
a. Some of the Group 2 metals react with oxygen to form oxides. Write the formulas for these
compounds.
b. Some of the Group 2 metals react with oxygen to form peroxides. Write the formulas for these
compounds.
c. Some of the Group 2 metals react with nitrogen to form nitrides. Write the formulas for these
compounds.
d. Most Group 2 elements form hydrides. What is hydrogen’s oxidation state in these compounds?

Kaitlynn Wade

Numerade Educator

Problem 55

Review the analytical tests for transition metals in the Elements Handbook (Appendix A), and answer
the following questions:
a. Determine the oxidation state of each metal in the precipitates shown for cadmium, zinc, and lead.
b. Determine the oxidation state of each metal in the complex ions shown for iron, manganese, and
cobalt.
c. The copper compound shown is called a coordination compound. The ammonia shown in the formula exists as molecules that do not have a charge. Determine copper’s oxidation state in this compound.

Himanshu Garg

Numerade Educator

Problem 56

Review the common reactions of Group 15 elements in the Elements Handbook (Appendix A), and answer the following questions:
a. Write formulas for each of the oxides listed for the Group 15 elements.
b. Determine nitrogen’s oxidation state in the oxides listed in (a).

Kaitlynn Wade

Numerade Educator

Problem 57

Nomenclature Biologists who name newly discovered organisms use a system that is structured very much like the one used by chemists in naming compounds. The system used by biologists is called the Linnaean system of binomial nomenclature, after its creator, Carolus Linnaeus. Research this system in a biology textbook, and then note similarities and differences between the Linnaeus system and chemical
nomenclature.

Tate Hilken

Numerade Educator

Problem 58

Common Chemicals Find out the systematic chemical name and write the chemical formula for each of the following common compounds:
a. baking soda d. limestone
b. milk of magnesia e. lye
c. Epsom salts f. wood alcohol

Charles Thomas

Numerade Educator

Problem 59

Performance Assessment Your teacher will supply you with a note card that has one of the following formulas on it: ${NaCH}_{3} {COO} \cdot 3 {H}_{2} {O}, {MgCl}_{2} \bullet 6 {H}_{2} {O}$ ${LiC}_{2} {H}_{3} {O}_{2} \cdot 2 {H}_{2} {O},$ or ${MgSO}_{4} \cdot 7 {H}_{2} {O}$ . Design an experiment to determine the percentage of water by mass in the hydrated salt assigned to you. Be sure to explain what steps you will take to ensure that the salt is completely dry. If your teacher approves your design, obtain the salt and perform the experiment. What percentage of water does the salt contain?

David Collins

Numerade Educator

Problem 60

Both ammonia, NH_ and ammonium nitrate, ${NH}_{4} {NO}_{3}$ are used in fertilizers as a source of nitrogen. Which compound has the higher percentage of nitrogen? Research the physical properties of both compounds, and find out how each compound is manufactured and used. Explain why each com-
pound has its own particular application. (Consider factors such as the cost of raw ingredients, the ease of manufacture, and shipping costs.)

Crystal Wang

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