CHEMISTRY CHAPTER 3

Exercise 3.28: Problems by Topic - Chemical Formulas and Molecular View of Elements and Compounds

Part A
Which of the following elements have molecules as their basic units?
Check all that apply.
fluorine
lead
nitrogen
bromine

Exercise 3.30: Problems by Topic - Chemical Formulas and Molecular View of Elements and Compounds
Classify each of the following compounds as ionic or molecular.

Part A
CF₂ Cl₂
molecular
ionic

Part B
CO
ionic
molecular

Part C
ClO₂
ionic
molecular

Part D
NI3
molecular
ionic

Exercise 3.34: Problems by Topic - Formulas and Names for Ionic Compounds

Write a formula for the ionic compound that forms between each of the following pairs of elements.

Part A
caesium and chlorine
Express your answer as a chemical formula.

Part B
aluminum and nitrogen
Express your answer as a chemical formula.

Part C
sodium and oxygen
Express your answer as a chemical formula.

Part D
barium and bromine
Express your answer as a chemical formula.

Exercise 3.46: Problems by Topic - Formulas and Names for Ionic Compounds

Write a formula for each of the following ionic compounds.

Part A
lead(II) chloride
Express your answer as a chemical formula.

Part B
iron(II) iodate
Express your answer as a chemical formula.

Part C
potassium chromate
Express your answer as a chemical formula.

Part D
potassium fluoride
Express your answer as a chemical formula.

Part E
iron(III) hydroxide
Express your answer as a chemical formula.

Part F
calcium phosphate
Express your answer as a chemical formula.

Exercise 3.58: Problems by Topic - Formula Mass and the Mole Concept for Compounds

Calculate the formula mass for each of the following compounds.

Part A
MgBr₂
Express your answer using two decimal places.
formula mass =

Part B
H₃ PO₄
Express your answer using two decimal places.
formula mass =

Part C
CBr₄
Express your answer using two decimal places.
formula mass =

Part D
FeCl₂
Express your answer using two decimal places.
formula mass =

Exercise 3.66: Problems by Topic - Composition of Compounds

Calculate the mass percent composition of nitrogen in each of the following nitrogen compounds.

Part A
N₂ O₅
Express your answer using four significant figures.
mass %N =

Part B
Si₃ N₄

Express your answer using four significant figures.
mass %N =

Part C
NO₂
Express your answer using four significant figures.
mass %N =

Part D
HNO₃
Express your answer using four significant figures.
mass %N =

Exercise 3.72: Problems by Topic - Composition of Compounds

The American Dental Association recommends that an adult female should consume 3.0 mgof fluoride (F-) per day to prevent tooth decay.

Part A
If the fluoride is consumed as sodium fluoride (45.24% F), what amount of sodium fluoride contains the recommended amount of fluoride?
Express your answer using two significant figures.
m =

Exercise 3.80: Problems by Topic - Chemical Formulas from Experimental Data

Samples of several compounds are decomposed and the masses of their constituent elements are shown below. Calculate the empirical formula for each compound.

Part A
1.245 gNi, 5.381 gI
Express your answer as a chemical formula.

Part B
2.677 gBa, 1.382 gCl
Express your answer as a chemical formula.

Part C
14.980 gCu, 7.557 gS, 15.10⁷ gO
Express your answer as a chemical formula.

Exercise 3.86: Problems by Topic - Chemical Formulas from Experimental Data

The molar mass and empirical formula of several compounds are listed below. Find the molecular formula of each compound.

Part A
C₄ H₉ , 114.27 g/mol
Express your answer as a chemical formula.

Part B
CCl, 189.82 g/mol
Express your answer as a chemical formula.

Part C
C₃ H₂ N, 208.25 g/mol
Express your answer as a chemical formula.

Exercise 3.94: Problems by Topic - Writing and Balancing Chemical Equations

When iron rusts, solid iron reacts with gaseous oxygen to form solid iron(III) oxide.

Part A
Write a balanced chemical equation for this reaction.
Express your answer as a chemical equation. Identify all of the phases in your answer.

Exercise 3.119: Cumulative Problems

Combustion analysis of a 13.42-g sample of estradiol (which contains only carbon, hydrogen, and oxygen) produced 39.01 gCO₂ and 10.65 gH₂ O. The molar mass of estradiol is 272.38g/mol .

Part A
Find the molecular formula for estradiol.
Express your answer as a chemical formula.

Exercise 3.60: Problems by Topic - Formula Mass and the Mole Concept for Compounds
Calculate the mass (in g) of each of the following.

Part A
5.59×10²⁰ SO₃ molecules
m1 =

Part B
2.4×10²² H₂ O molecules
Express your answer using two significant figures.
m2 =

Part C
4.8×10²⁵ O₃ molecules
Express your answer using two significant figures.
m3 =

Part D
9.77×10¹⁹ CCl₂ F₂ molecules
m4 =