Easy! We breath oxygen, O2 and exhale carbon dioxide, CO2. Plants also give off oxygen, O2 and utilize CO2.
We eat salt, NaCl and drink water, H2O.
Some coins we use are made of silver, Si, copper, Cu2+ or nickel, Ni.
We wrap sandwiches in aluminum, Al, foil. Table sugar is a 6 carbon ring named glucose. Sugar in fruit is a five carbon ring called fructose.
Some cleaning chemicals, like bleach or vinegar can be toxic or dangerous to people and animals. Chemicals that are either very acidic or alkaline can be toxic/dangerous to people and animals.
Keep them away from children and always use care when using these liquid cleaners.