AnswersChemistryAcids and Bases

Acids and Bases — Test Answers

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What type of substance reacts with limestone open paren CaCO sub 3 close paren and produces carbon dioxide gas?

A
both an acid and a base
B
a neutral substance
C
an acid
D
a base
2
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What is the definition of a Lewis base?

A
a substance that accepts electrons to form a covalent bond
B
a substance that when dissolved in water increases hydrogen ion concentration
C
a substance that donates a proton
D
a substance that donates electrons to form a covalent bond
3

What does it mean for a strong base to be in equilibrium?

A
There is a great deal of base and very few ions.
B
The position of equilibrium lies far to the right, with products being favored.
C
The position of equilibrium lies far to the left, with products being favored.
D
There is an equal amount of reactants and products.
4

The table lists some acids and bases. Strong acids Weak acids Weak bases Strong bases HBr CH sub 3 COOH NH sub 3 NaOH HNO sub 3 HCOOH NH sub 4 OH KOH cap h sub 2 SO sub 4 Ca OH sub 2 Which reaction yields a salt that has a pH is less than 7 ?

A
cap n cap h sub 3 plus cap h cap n cap o sub 3
B
cap h cap c cap o cap o cap h plus cap k cap o cap h
C
cap c A cap o cap h 2 plus cap h sub 2 cap s cap o sub 4
D
cap k cap o cap h plus cap h cap b r
5

Which of these correctly defines the pOH of a solution?

A
the negative log of the hydronium ion concentration
B
the log of the hydroxide ion concentration
C
the negative log of the hydroxide ion concentration
D
the log of the hydronium ion concentration
6

Which statement best describes the use of a chemical indicator in a titration?

A
It must measure pH directly at all pH values.
B
It must change color near the equivalence point.
C
It must be measured to the nearest 0 point 0 1 milliliters .
D
It must be colored in the acid solution.
7

A strong acid, HA , is added to water. Which statement about the solution is true?

A
It contains little or no HA .
B
It contains mostly hydroxide ions.
C
It contains a low amount of ions.
D
It contains almost no hydronium ions.
8

Which describes the titration graph when a weak acid is titrated by a strong base?

A
It begins at a low pH and has an equivalence point greater than 7 .
B
It begins at a high pH and has an equivalence point less than 7 .
C
It begins at a high pH and has an equivalence point of 7 .
D
It begins at a low pH and has an equivalence point of 7 .
9

Consider this reaction. Na raised to the plus plus cap c power sub 2 cap h sub 3 cap o sub 2 raised to the negative aq power plus cap h raised to the plus plus Cl raised to the negative right arrow cap n raised to the plus plus Cl raised to the negative plus HC power power sub 2 cap h sub 3 cap o sub 2 power power Which is the net ionic equation for the reaction?

A
Na raised to the plus plus cap c power sub 2 cap h sub 3 cap o sub 2 raised to the negative right arrow NaC sub 2 cap h sub 3 cap o sub 2 power
B
cap h raised to the plus plus Cl raised to the negative right arrow HCl power power
C
Na raised to the plus plus Cl raised to the negative right arrow NaCl power power
D
cap c sub 2 cap h sub 3 cap o sub 2 raised to the negative aq power plus cap h raised to the plus right arrow HC sub 2 cap h sub 3 cap o sub 2 power
10

Which of these substances is an Arrhenius acid?

A
BF sub 3
B
NH sub 3
C
Mg OH sub 2
D
HCN
11

Consider the reaction. NH sub 4 raised to the plus plus cap h power sub 2 cap o rightarrow NH sub 3 plus cap h sub 3 cap o raised to the plus power Which is an acid-conjugate base pair?

A
cap h sub 2 cap o and NH sub 3
B
cap h sub 2 cap o and cap h sub 3 cap o raised to the plus power
C
NH sub 4 raised to the plus power and NH sub 3
D
NH sub 4 raised to the plus power and cap h sub 3 cap o raised to the plus power
12

A solution of ammonia has a pH of 11 point 8 What is the concentration of OH raised to the negative power ions in the solution? Useful formulas include open bracket cap h sub 3 cap o raised to the plus power close bracket is equal to 10 raised to the negative pH power , open bracket OH raised to the negative power close bracket is equal to 10 raised to the negative pOH power , pH plus pOH is equal to 14 and open bracket cap h sub 3 cap o raised to the plus power close bracket times open bracket OH raised to the negative power close bracket is equal to 10 to the negative 14 power

A
158 cap m
B
2 point 2 0 cap m
C
1 point 5 8 times 10 to the negative 12 power cap m
D
6 point 3 1 times 10 to the negative 3 power cap m
13

Soaps feel slippery on our hands because they dissolve the oil on our skin, decreasing friction.This is because soap contains

A
an acid.
B
a base.
C
a salt molecule.
D
a neutral molecule.
14

Which pair of substances would most likely result in the production of a gas when reacting with an acid?

A
metal and carbonate
B
carbon dioxide and water
C
litmus and methyl orange
D
base and salt
15

An unknown substance turns blue litmus paper to red. Which additional test could be used to confirm the substance’s identity?

A
It should turn methyl orange to orange because it is an acid.
B
It should turn phenolphthalein from pink to colorless because it is a base.
C
It should turn phenolphthalein from colorless to pink because it is a base.
D
It should turn methyl orange to red because it is an acid.
16

A salt is best described as a compound that is formed from the reaction between

A
an acid and a base.
B
an acid and water.
C
a strong acid and a weak acid.
D
a strong base and a weak base.
17

A group of students is comparing the graphs of strong acid-strong base and weak acid-strong base titration curves, where the base is the titrant. Which statement inaccurately describes a difference between the two curves?

A
At the equivalence points, the pH of the weak acid-strong base is greater than the pH of the strong acid-strong base.
B
The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve.
C
At the half-equivalence points, the pH of the weak acid-strong base is greater than the pH of the strong acid-strong base.
D
The steep-rise interval in the weak acid-strong base curve is more pronounced than in the strong acid-strong base curve.
18

Which of these refers to the strength of an acid?

A
a measure of the quantity of acid dissolved in water designated by molarity
B
the amount of hydrogen ions present in the acid
C
the amount of hydroxide ions present in a solution
D
an intrinsic characteristic of a particular acid, not related to concentration
19

Which characteristic do all titration graphs share?

A
The pH decreases as the reaction progresses.
B
The midpoint of a steep vertical section indicates the equivalence point.
C
The midpoint of a flat horizontal section indicates the equivalence point.
D
The pH increases as the reaction progresses.
20

Which of these is the correctly balanced chemical equation for the reaction of Ca OH sub 2 and HNO sub 3 ?

A
Ca OH sub 2 plus 2 HNO sub 3 rightarrow 2 cap h sub 2 cap o plus 2 NO sub 3 raised to the negative power
B
Ca OH sub 2 plus 2 HNO sub 3 rightarrow cap h sub 2 cap o plus CaNO sub 3
C
Ca OH sub 2 plus HNO sub 3 rightarrow Ca raised to the 2 plus power plus NO sub 3 raised to the negative power
D
Ca OH sub 2 plus 2 HNO sub 3 rightarrow 2 cap h sub 2 cap o plus Ca open paren NO sub 3 close paren sub 2

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