We can classify all matter into pure substances and ______

Distilled water is a _______, because it has the same chemical structure whether it is isolated from a river or made in a laboratory.

The air we breathe is a ________ because it is made of several different gases.

Which of these are pure substances?

• Drinking water

• Distilled water

• Salty water

• Water steam (steam = vapor)

• $H_2O$

Which of these are mixtures?

• Vinegar

• Salty water

• Air

• Carbon dioxide $\left(CO_2\right)$

• Steel (steel = acer)

A mixture contains _____ pure substances.

We separate mixtures into ____________ and ____________ depending on whether we can distinguish their components.

Which of these are homogeneous mixtures?

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In a homogeneous mixture...

• ... it is impossible to see the different components.

• ... there is no way to separate the components.

• ... the components always have similar chemical formulas.

• ... it is possible to see the different components.

In a heterogeneous mixture...

• ... it is impossible to see the different components.

• ... there is no way to separate the components.

• ... the components always have similar chemical formulas.

• ... it is possible to see the different components.