Pure Substances & Mixtures Flashcards

All 6 cards in this deck

In chemistry, what is a pure substance?

A single element or compound, not mixed with any other substance.

What is a mixture?

Two or more substances (elements and/or compounds) not chemically joined together.

How does the everyday use of the word 'pure' differ from its chemical meaning?

Everyday 'pure' means natural or with nothing harmful added; in chemistry it means a single element or compound only.

What does the melting point of a pure substance look like?

A sharp melting point — it melts at one fixed temperature.

True or false? A sample that melts between 52 °C and 58 °C is pure.

False. Melting over a range of temperatures shows it is a mixture.

True or false? Pure orange juice with no additives is a pure substance in the chemical sense.

False. It is a mixture of water, sugars, acids and other compounds.