Chemicals surround us all the time and influence our lives without us even noticing. Here you can see a few more examples of some chemical and physical reactions with everyday chemicals.
Many different chemical reactions produce gas. At home, why not try producing carbon dioxide gas. To do this, mix together vinegar, which is acidic, and baking powder, which is alkaline, in a jar. Make sure the jar is in a sink — watch the bubbles of carbon dioxide erupt over the edge of the jar!
Iron filings and sulphur can be mixed together. The iron filings can be easily separated from the mixture as they are attracted by a magnet. This is an example of a physical change. In a physical change, the material changes only its appearance. It is easy to reverse the change because no new substances are formed.
Eggs and bread are mixtures of compounds. When they are heated, new compounds are formed and a chemical reaction has taken place. We cannot undo this change in a simple way. Only complex chemical processes can reverse a chemical change.
How does evaporation work?
Ask an adult to help you boil a solution of salt and water. As the solution is heated, the tiny molecules move more rapidly. The water molecules eventually gain enough energy to fly off as gas. However, there’s not enough energy for the salt to boil, and it is left behind.