you will be frequently asked to weight small amounts of chemical to make up solutions. this will involve using balances ,which will give the mass to either two or three decimal places in grams. A common procedure in the use of these balances is taring,which means to remove the weight of the container holding the chemical by setting the scale to zero while the container is on the balance . Increases in the reading on the balance would then be accounted to the mass of the substance added.