Acids, Alkalis and Metals
How we use them in our everyday lives
USEFUL REACTIONS
Acid + magnesium oxide = neutralisation
Magnesium is an element your body needs to function normally. Some people use it as an antacid to relieve heartburn, sour stomach, or acid indigestion. Magnesium oxide also may be used as a laxative for short-term, rapid emptying of the bowel (before surgery, for example). Magnesium oxide also is used as a dietary supplement when the amount of magnesium in the diet is not enough.
(combustion)
Anything can burn at the right temperature bit a lot of things don't catch fire. Humans have used fire from as far back as the cavemen as it provides us heat and light. Alternitavly combustion can be a bad thing eg. A house burning down.
Cooking food
Cooking food is a great example of a reaction. It matches the colour changing rule that it will change colour when cooked and it will also change density.
Non useful reactions
Metal + Oxygen = metal oxide (rusting)
When iron is exposed to water and oxygen it forms rust.
Co2
Co2 emmisions are being produced all the time all over the world by cars, factories and even cowes farting.