Elements

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Slide 9

Pure substances

A pure substance can be a solid, liquid, or gas.

A pure substance has all the same atoms or molecules.

An example of a pure substance is pure water.

Here are some pure substances: sugar, ice cubes, and baking soda

Slide 10

Mixtures

A mixture is matter made up of two or more different types of particles.

A mixture can be separated into its different types of particles.

An example of a mixture is salt water. You can separate the salt from the water if you evaporate the water.

This is a mixture of different candies.

Slide 11

Carbon!

Carbon is the element most important to life because it is good at making very large molecules like DNA

Pencils use pure carbon (graphite) to write

Diamonds are also pure carbon

Structure of graphite

Structure of DNA

Slide 12

Table salt: Friend or enemy?

Some elements are safe sometimes and dangerous other times

Table salt is made of sodium and chlorine, but pure sodium will explode if it touches water and chlorine is a poisonous gas used in warfare.

A small piece of sodium exploding in water

Chlorine gas was used in battle in World War I

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Table salt