AnswersEO Chemistry 7320BUnit Test

Unit Test — Unit test Answers

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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
2
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Which statement highlights a unique role of water in a biological system?

A
Organisms cannot use it to regulate their body temperature.
B
Few organisms can use it as a living environment.
C
It does not provide structural support to organisms.
D
It provides organisms a medium to transport materials.
3

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
4

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
5

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
6

Which term refers to the process by which ions that have entered solution are kept in solution?

A
dissociation
B
electrolyte
C
hydration
D
ionization
7

Which reaction will produce a solution that does not conduct electricity?

A
CH3OH(l) CH3OH(aq)
Option A
B
CaBr2(s) Ca2+(aq) + 2Br(aq)
Option B
C
HF(g) + H2O(l) H3O+(aq) + F–(aq)
Option C
D
NH3(g) + H2O(l) NH4+(aq) + OH–(aq)
Option D
8

Which is a characteristic of super-absorbent polymers?

A
When they absorb water, they become gels.
B
They bind to water in stoichiometric ratios.
C
They have a single water-absorbing monomer per molecule.
D
Each monomer is a salt of a carboxylic acid that repels water.
9

A sample of a hydrated compound has a mass of 5.1 g. During heating, it loses 1.1 g, leaving 4.0 g. What is the percentage by mass of water in the original hydrate?Use the formula

Question illustration
A
6.11%
B
21.6%
C
27.5%
D
78.4%
10

What happens to water when it freezes?

A
Its mass increases.
B
Its mass decreases.
C
Its density increases.
D
Its density decreases.
11

Which contributes to the polarity of a water molecule?

A
a linear shape along with strong covalent bonds
B
deflection of hydrogen atoms by lone pairs of electrons
C
no difference in the electronegativity of oxygen and hydrogen
D
hydrogen bond formation between water molecules
12

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.
13

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
14

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
15

Which is the best name for the compound CaSO4•2H2O?

A
hydrated calcium sulfate
B
calcium sulfate trihydrate
C
calcium sulfate dihydrate
D
anhydrous calcium sulfate
16

Which correctly describes the relationship between a hydrate, water, and an anhydrous compound?

A
Heating an anhydrous compound forms water and a hydrate.
B
Adding water to an anhydrous compound forms a hydrate.
C
Combining an anhydrous compound and a hydrate produces water.
D
Removing a hydrate from an anhydrous compound produces water.
17

Consider the equation below.Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g)Which compound is the gas in this chemical reaction?

Question illustration
A
Mg
B
HCl
C
MgCl2
D
H2
18

Which describes a property of water that allows plants to transfer it from their roots to their leaves?

A
Water exhibits weak adhesion and cohesion, which allows capillary action to occur.
B
Water exhibits strong adhesion and cohesion, which allows capillary action to occur.
C
Water has low surface tension, which prevents capillary action from occurring.
D
Water has high surface tension, which prevents capillary action from occurring.
19

Which substance will most likely dissociate when it is dissolved in water?

A
NO2
B
N2F6
C
CaCl2
D
C6H12O6
20

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

A
colloid
B
compound
C
element
D
suspension

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