A sulphate is a kind of chemical compound that has sulphur and oxygen in it.
Sulphates are often used in cleaning products and medicines.
Examples:
I need to buy some sulphate for my science experiment.
The shampoo has sulphate in it.
Sulphate is used in making some kinds of medicine.
Don't drink that, it has sulphate in it!
Sulphate is very important for some kinds of cleaning.
The scientist mixed the sulphate into the liquid and watched what happened.