AnswersLA-Chemistry AElements, Compounds, and Mixtures

Elements, Compounds, and Mixtures Answers

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Which is a pure substance?

A
soda
B
gasoline
C
salt water
D
carbon dioxide
2
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A gravel can be broken down into different kinds of substances by physical processes. No chemical reactions are needed to separate different parts of gravel into pure substances. This is because gravel is a(n)

A
compound
B
element
C
homogeneous mixture
D
heterogeneous mixture
3

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
4

Which best describes a compound such as sodium chloride?

A
a pure substance that can be separated into different elements by physical means
B
a mixture of two common substances that can be separated by chemical means
C
a mixture of two common elements that can be separated by physical means
D
a pure substance that can be separated into different elements by chemical means
5

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
6

Which is a substance that is made up of only one type of atom?

A
compound
B
element
C
solution
D
mixture
7

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.
8

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.
9

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
10

Which sample is a pure substance?

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

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