Practice Pure Substance in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Worksheet PDF Free Answer-key PDF Family

Quick Recap

A sample of matter that has a fixed, definite chemical composition throughout, consisting of only one type of element or one type of compound.

Every particle in a pure substance is the same. Pure water is all H₂O — no exceptions.

Showing a random 20 of 50 problems.

Example 1

challenge
Argue whether 'pure 24-karat gold jewelry' truly meets the chemistry definition of a pure substance, while 18-karat gold does not.

Example 2

hard
Is 24-karat gold a pure substance? Why or why not?

Example 3

challenge
You are given pure water, salt water, and pure NaClNaCl. Rank them as pure substance or mixture, and explain why salt water is the odd one out.

Example 4

medium
Brass is copper and zinc melted together uniformly. Classify it and name the larger-amount idea.

Example 5

hard
A student claims 'any colorless liquid that boils at 100 °C is pure water.' Is this true?

Example 6

easy
Is a diamond (pure carbon, C) a pure substance?

Example 7

easy
Is helium gas in a balloon a pure substance?

Example 8

medium
Graphite (pure C) and a graphite pencil 'lead' (graphite plus clay) are compared. Which is the pure substance?

Example 9

easy
Is sugar (C12H22O11\text{C}_{12}\text{H}_{22}\text{O}_{11}) a pure substance?

Example 10

medium
Two unlabeled clear liquids are heated. Liquid A boils at exactly 78.4 °C the entire time. Liquid B's temperature drifts from 70 °C to 95 °C while boiling. Which is the pure substance?

Example 11

hard
Pure carbon dioxide (CO2\text{CO}_2): element or compound?

Example 12

easy
Pure substances are split into two categories. Name them.

Example 13

easy
Is a bar of pure gold (Au) a pure substance?

Example 14

easy
Is pure oxygen gas, O2O_2, a pure substance?

Example 15

medium
Can a pure substance be broken down into simpler substances by physical means?

Example 16

easy
Is table salt, NaClNaCl, a pure substance?

Example 17

medium
What kind of mixture is one where you can see the separate parts (like a salad)?

Example 18

easy
Is distilled water (H2OH_2O) a pure substance?

Example 19

medium
A clear liquid boils completely at exactly 100 °C at 1 atm. What does the constant boiling point suggest?

Example 20

medium
How can you determine whether a clear liquid is a pure substance or a mixture?
← Back to Pure Substance Worked Examples