Chapter 4
Types of Chemical Types of Chemical Reactions and Solutions Reactions and Solutions
StoichiometryStoichiometry
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–2
QUESTION
An unknown substance dissolves readily in water but not in benzene (a nonpolar solvent). Molecules of what type are present in the substance? 1) Neither polar nor nonpolar 2) Polar 3) Either polar or nonpolar 4) Nonpolar 5) none of these
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–3
ANSWER
2) Polar
Section 4.1 Water, the Common Solvent (p. 127)
The solubility rule for molecular compounds is “like dissolves like”, that is, polar molecules dissolve in polar solvents and nonpolar molecules dissolve in nonpolar solvents.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–4
QUESTION
How many grams of NaCl are contained in 350. mL of a 0.250 M solution of sodium chloride? 1) 41.7 g 2) 5.11 g 3) 14.6 g 4) 87.5 g 5) None of these
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–5
ANSWER
2) 5.11 g
Section 4.3 The Composition of Solutions(p. 133)
Volume (L) times concentration (mol/L) gives moles. Moles are then converted to grams.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–6
QUESTION
What volume of 18.0 M sulfuric acid must be used to prepare 15.5 L of 0.195 M H2SO4? 1) 168 mL 2) 0.336 L 3) 92.3 mL 4) 226 mL 5) None of these
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–7
ANSWER
M 1 2 V ,
V
1) 168 mL
Section 4.3 The Composition of Solutions(p. 133)
Use the dilution formula, 1 V = M 2 M is in mol/L and is in L.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–8
QUESTION
The net ionic equation for the reaction of aluminum sulfate and sodium hydroxide contains which of the following species? 1) 3Al
3+(aq)
2) OH–(aq)
3) 3OH–(aq)
4) 2Al3+
(aq) 5) 2Al(OH)3(s)
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–9
ANSWER
–
3) 3OH(aq)
Section 4.6 Describing Reactions in Solution(p. 145)
The net ionic equation is found by canceling the spectator ions from the total ionic equation.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–10
QUESTION
Which of the following is a strong acid? 1) HF 2) KOH 3) HClO4 4) HClO 5) HBrO
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–11
ANSWER
4
:
3) HClO
Section 4.2 The Nature of Aqueous SolutionsStrong and Weak Electrolytes (p. 129)
Memorization of the list of strong acids will allow one to determine the difference between strong acids and weak acids.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–12
QUESTION
All of the following are weak acids except: 1) HCNO. 2) HBr. 3) HF. 4) HNO2. 5) HCN.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–13
ANSWER
.
2) HBr
Section 4.2 The Nature of Aqueous Solutions: Strong and Weak Electrolytes (p. 129)
Knowing the list of strong acids will allow one to determine which acids are strong and which are weak.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–14
QUESTION
Which of the following is not a strong base? 1) Ca(OH)2 2) KOH 3) NH3 4) LiOH 5) Sr(OH)2
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–15
ANSWER
3
3) NH
Section 4.2 The Nature of Aqueous Solutions: Strong and Weak Electrolytes (p. 129)
Knowing the list of strong bases will allow one to determine which bases are strong and which are weak.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–16
QUESTION
The interaction between solute particles and water molecules, which tends to cause a salt to fall apart in water, is called: 1) hydration. 2) polarization. 3) dispersion. 4) coagulation. 5) conductivity.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–17
ANSWER
.
1) hydration
Section 4.1 Water, the Common Solvent (p. 127)
Hydration is the process of water molecules surrounding and stabilizing ions so that they can be pulled into solution.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–18
QUESTION
The concentration of a salt water solution that sits in an open beaker decreases over time.
1) True 2) False
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–19
ANSWER
2) False
Section 4.3 The Composition of Solutions(p. 133)
The amount of water decreases over time so the concentration (mol NaCl/volume of water) increases over time.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–20
QUESTION
The following reactions: Pb
2+ + 2I
– PbI2
2Ce4+ + 2I
– I2 + 2Ce
3+
HOAc + NH3 NH4
+ + OAc
–
are examples of
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–21
QUESTION (continued)
1) acid-base reactions. 2) unbalanced reactions. 3) precipitation, acid-base, and redox
reactions, respectively. 4) redox, acid-base, and precipitation
reactions, respectively. 5) precipitation, redox, and acid-base
reactions, respectively.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–22
ANSWER
-
24+ 3+
3
5) precipitation, redox, and acid base reactions, respectively.
Section 4.5 Precipitation Reactions (p. 140)
PbI is insoluble, Ce changes to Ce and HOAc is an acid while NH is a base.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–23
QUESTION
Which of the following salts is insoluble in water? 1) Na2S 2) K3PO4 3) Pb(NO3)2 4) CaCl2 5) All of these are soluble in water.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–24
ANSWER
5) All of these are soluble in water.
Section 4.5 Precipitation Reactions (p. 140)
According to the solubility rules for ionic compounds, compounds containing Group IA ions or nitrate ions will always be soluble. Compounds containing halides are generally soluble, aside from silver, lead and mercury(I) halides.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–25
QUESTION
When NH3(aq) is added to Cu2+
(aq), a precipitate initially forms. Its formula is: 1) Cu(NH3)4
2+
2) Cu(NO3)2 3) Cu(OH)2 4) Cu(NH3)4
2+
5) CuO
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–26
ANSWER
2
s
3 4+
3) Cu(OH)
Section 4.4 Types of Chemical Reaction(p. 140)
Ammonia produces hydroxide ion in water:NH + H2O NH + OH
–
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–27
QUESTION
In the balanced molecular equation for the neutralization of sodium hydroxide with sulfuric acid, the products are: 1) NaSO4 + H2O 2) NaSO3 + 2H2O 3) 2NaSO4 + H2O 4) Na2S + 2H2O 5) Na2SO4 + 2H2O
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–28
ANSWER
5) Na2SO4 + 2H2O Section 4.8 Acid-Base Reactions (p. 149) The salt is made from the anion of the acid and the cation of the base.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–29
QUESTION
What mass of NaOH is required to react exactly with 25.0 mL of 1.2 M H2SO4? 1) 1.2 g 2) 1.8 g 3) 2.4 g 4) 3.5 g 5) None of these
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–30
ANSWER
-
2 4
2 4 2
2
3) 2.4 g
Section 4.8 AcidBase Reactions (p. 149)
Remember that the reaction is 2NaOH + H SO Na SO + 2H O, so there are two moles of
NaOH used per one mole of H SO4.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–31
QUESTION
In which of the following does nitrogen have an oxidation state of +4? 1) HNO3 2) NO2 3) N2O 4) NH4Cl 5) NaNO2
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–32
ANSWER
2
-
–
2O2
2) NO
Section 4.9 Oxidation Reduction Reactions(p. 154)
Oxygen almost always has an oxidation state of 2 when part of a compound. The exception is
when it is part of a peroxide. For example, hydrogen peroxide H . Then it has an oxidation state of –1.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–33
QUESTION
In the reaction 2Cs(s) + Cl2(g) 2CsCl(s), Cl2 is 1) the reducing agent. 2) the oxidizing agent. 3) oxidized. 4) the electron donor. 5) two of these
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–34
ANSWER
-
2) the oxidizing agent.
Section 4.9 Oxidation Reduction Reactions(p. 154)
Metals lose electrons, so they are oxidized, making the other reactant an oxidizing agent.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–35
QUESTION
Which of the following statements is(are) true? Oxidation and reduction: 1) cannot occur independently of each other. 2) accompany all chemical changes. 3) describe the loss and gain of electron(s),
respectively. 4) result in a change in the oxidation states of
the species involved. 5) 1, 3, and 4 are true
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–36
ANSWER
.
-
5) 1, 3, and 4 are true
Section 4.9 Oxidation Reduction Reactions(p. 154)
(2) is false because certain reactions, such as double displacement reactions, are not redox reactions.
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–37
QUESTION
How many of the following are oxidation-reduction reactions? NaOH + HCl NaCl + H2O Cu + 2AgNO3
2Ag + Cu(NO3)2 Mg(OH)2
MgO + H2O N2 + 3H2
2NH3
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–38
QUESTION (continued)
1) 0 2) 1 3) 2 4) 3 5) 4
Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 4–39
ANSWER
-
3) 2
Section 4.9 OxidationReduction Reactio ns(p. 154)
If an element is found on the reactant’s side, this is almost always a redox reaction, since an element usually becomes part of a compound during a chemical reaction.