Pure Substance Chemistry Example 1

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Example 1

easy
Distinguish between a pure substance and a mixture. Give two examples of each.

Solution

  1. 1
    A pure substance has a fixed composition and distinct properties: elements (e.g., gold) and compounds (e.g., water H2O\text{H}_2\text{O}).
  2. 2
    A mixture is a combination of two or more substances in variable proportions: (e.g., salt water, air).
  3. 3
    Mixtures can be separated by physical means; pure substances cannot (compounds require chemical methods).

Answer

Pure: Au, H2O.Mixtures: salt water, air.\text{Pure: Au, H}_2\text{O.}\quad\text{Mixtures: salt water, air.}
Classification of matter starts with distinguishing pure substances from mixtures. Pure substances have uniform and definite composition throughout.

About Pure Substance

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

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More Pure Substance Examples

Example 2 medium

How can you determine whether a clear liquid is a pure substance or a mixture?

Example 3 easy

Is orange juice a pure substance or a mixture? Explain.

Example 4 hard

Both distilled water and steel are uniform in appearance and properties. Explain why distilled water

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