Answers2026-2027_MDCPS_2003345_Chemistry_1_B-CRLab: Measuring pH

Lab: Measuring pH — Unit test Answers

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1
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Which of the following substances is an Arrhenius acid?

A
BF3
B
HCN
C
NH3
D
Mg(OH)2
2
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What is the definition of a Lewis base?

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

Which statements are true of heterogeneous mixtures? 1) They settle out. 2) The proportions of solute to solvent may vary. 3) The solute is evenly distributed throughout. 4) They are composed of two solvents and two solutes.

A
1 and 2
B
2 and 4
C
3 only
D
2 only
4

The picture below shows a mixture that was stirred 3 minutes ago.What should this mixture be classified as?

Question illustration
A
colloid
B
compound
C
solution
D
suspension
5

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

A
litmus and methyl orange
B
base and salt
C
metal and carbonate
D
carbon dioxide and water
6

What type of substance reacts with limestone (CaCO3) and produces carbon dioxide gas?

A
a neutral substance
B
a base
C
an acid
D
both an acid and a base
7

Which is true about the dissolving process in water?

A
Polar solutes do not dissolve easily in water.
B
Water molecules are attracted by solute ions at the surface of the solute.
C
Water molecules move throughout the solute.
D
Solute molecules pull water molecules away from the surface.
8

What is the name of a solution whose concentration of solute is equal to the maximum concentration that is predicted from the solute's solubility?

A
dilute
B
saturated
C
unsaturated
D
supersaturated
9

A solution of HCl has = 0.01 M. What is the pH of this solution?Use .

Question illustration
A
–2
B
–1
C
1
D
2
10

Which of these correctly defines the pOH of a solution?

A
the log of the hydronium ion concentration
B
the negative log of the hydronium ion concentration
C
the log of the hydroxide ion concentration
D
the negative log of the hydroxide ion concentration
11

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

A
a neutral molecule.
B
a salt molecule.
C
an acid.
D
a base.
12

What type of mixture scatters light and cannot be filtered easily?

A
a colloid, a heterogeneous mixture
B
a solution, a heterogeneous mixture
C
a colloid, a homogeneous mixture
D
a solution, a homogeneous mixture
13

A solution of ammonia has a pH of 11.8. What is the concentration of OH– ions in the solution?Useful formulas include , , , and .

Question illustration
A
1.58 10–12 M
Option A
B
6.31 10–3 M
Option B
C
2.20 M
D
158 M
14

Which description correctly characterizes the acidity or basicity of a solution?

A
The higher the pH is, the more the hydroxide ion concentration decreases and the more acidic the solution becomes.
B
The higher the pH is, the more the hydroxide ion concentration increases and the more basic the solution becomes.
C
The lower the pH is, the more the hydronium ion concentration decreases and the more acidic the solution becomes.
D
The lower the pH is, the more the hydronium ion concentration increases and the more basic the solution becomes.
15

Lewis acids and bases are most closely associated with which process?

A
proton transfer
B
electron transfer
C
the formation of aqueous ions
D
the formation of a conjugate acid or base
16

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 phenolphthalein from colorless to pink because it is a base.
B
It should turn phenolphthalein from pink to colorless because it is a base.
C
It should turn methyl orange to orange because it is an acid.
D
It should turn methyl orange to red because it is an acid.
17

The table below shows four samples of carbon dioxide gas and the temperature of the water that they were dissolved in.SampleTemperature of water (°C)1 782 733 554 63Which of the samples most likely had the lowest solubility?

A
1
B
2
C
3
D
4
18

Which heterogeneous mixture contains large particles that can settle out or can be filtered?

A
colloid
B
compound
C
element
D
suspension
19

Which factor causes a decrease in the rate of dissolution?

A
decreasing the amount of solute
B
increasing the stirring of the solution
C
decreasing the surface area of the solute
D
increasing the temperature of the solvent
20

Consider the reaction below.NH4+ + H2O NH3 + H3O+Which is an acid-conjugate base pair?

Question illustration
A
NH4+ and NH3
B
NH4+ and H3O+
C
H2O and NH3
D
H2O and H3O+

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