Answers26-27 CFISD TX-Chemistry A CRLab: Physical and Chemical Changes

Elements, Compounds, and Mixtures Answers

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Bromine, a liquid at room temperature, has a boiling point of 58°C and a melting point of –7.2°C. Bromine can be classified as a

A
compound.
B
impure substance.
C
mixture.
D
pure substance.
2
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A solid precipitate is formed from the reaction of lead nitrate and sodium chromate. What would be the best method to separate this solid from the solution?

A
distillation
B
evaporation
C
filtration
D
sorting
3

A teacher makes the following statement.“Gasoline boils at a relatively low temperature (about 150°C). The kerosene is removed at around 200°C, followed by diesel oil at 300°C and fuel oil at around 370°C.”What topic is the teacher most likely talking about?

A
distillation of a mixture
B
filtration of a pure substance
C
evaporation of a mixture
D
sorting of a pure substance
4

A chemist is studying an unknown substance and could break the substance into its elemental components only by using chemical means. Based on this observation, how should the unknown substance be classified?

A
impure substance
B
solution
C
mixture
D
pure substance
5

Which sample is a pure substance?

A
zinc oxide
B
sugar dissolved in water
C
pond water
D
soil
6

Which is a characteristic of mixtures?

A
They are chemically bonded together.
B
They can be classified as pure substances.
C
They have fixed ratios between their components.
D
They can be separated by physical processes.
7

The chemical formula for an emerald is Be3Al2(SiO3)6. An emerald can be described as

A
a pure substance because it is a compound.
B
a pure substance because it is an element.
C
an impure substance because it is chemically combined.
D
an impure substance because it is a mixture.
8

Which best describes an element?

A
a pure substance
B
a type of a mixture
C
a pure compound
D
an impure substance
9

The table shows the percentages of hydrocarbons that are found in a sample of crude oil.HydrocarbonsPercentageparaffins30naphthenes49aromatics15asphaltics6.0Based on the given information, what is the best classification for this sample of crude oil?

A
an element
B
a pure compound
C
a pure substance
D
a mixture
10

Which is a pure substance?

A
soda
B
gasoline
C
salt water
D
carbon dioxide

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