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Properties of Matter Element Card 15, Lesson 21

Phosphorus

P

Melting point

44.1° C

Boiling point

280° C

Density

1.8 g/cm³

Appearance

Phosphorus occurs in more than one form. One of these is waxy and white, and another is a dark, red powder.

Other physical properties

The waxy, white form of phosphorus glows in the dark.

Chemical properties

Phosphorus is insoluable in water. The waxy, white form is very reactive and can explode in air. (It burns at 35 °C.) It is also very poisonous. The powdery form is less reactive, although it burns in air. It is not very toxic.

Compounds

Calcium phosphate, a natural rock used to make phosphate fertilizers, is one compound of phosphorus.

Uses

Phosphorus is alloyed with bronze. It is also used in incendiary bombs and match heads.

Notes

Phosphorus compounds play an important role in the use of energy in living things.

Match heads are made from phosphorus compounds, which ignite when rubbed against a rough surface.

         

phosphorus in oil   Calcium phosphate being mined

Phosphorus comes in a red and a white form. This photograph shows the white form, which is more reactive, stored in oil. Why is it stored in oil?

 

Calcium phosphate, the most widely used phosphorus compound, is mined in Florida. It is used to make fertilizer.

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