11-1 What is air?

Air is matter…it has mass and volume. A Mixture of Gases Air is made mostly of nitrogen (78%) and oxygen (21%) and other trace gases. Air is matter…it has mass and volume.

Nitrogen Bacteria have to change nitrogen gas into nitrogen compounds that living things can use. Plants get N compounds from the ground, then animals get N compounds by eating the grass.

Oxygen Living things need oxygen to carry on cellular respiration. Cellular respiration- process by which a cell releases energy from food molecules. As O is breathed in, this process is completed.

Carbon Dioxide Carbon dioxide is given off by things burning…such as in pollution. Humans also give off carbon dioxide as a byproduct of breathing. Plants then take in carbon dioxide to make their food. (Draw 2 and 3).

Components in Air Gases such as N, O, and CO2. Water vapor- steam- gases. Tiny particles of dust, smoke, salt, and other chemicals.