Reacting Masses

Reacting Massesvideo

Reacting Masses

• Chemical equations can be used to calculate the moles or masses of reactants and products

• To do this, information given in the question is used to find the amount in moles of the substances being considered

• Then, the ratio between the substances is identified using the balanced chemical equation

• Once the moles have been determined they can then be converted into grams using the relative atomic or relative formula masses

Limiting Reactants

• A chemical reaction stops when one of the reactants is used up

• The reactant that is used up first is the limiting reactant, as it limits the duration and hence the amount of product that a reaction can produce

• The amount of product is therefore directly proportional to the amount of the limiting reactant added at the beginning of a reaction

• The limiting reactant is the reactant which is not present in excess in a reaction

• In order to determine which reactant is the limiting reactant in a reaction, we have to consider the ratios of each reactant in the balanced equation

• When performing reacting mass calculations, the limiting reactant is always the number that should be used as it indicates the maximum possible amount of product

• The steps are:

  1. Write the balanced equation for the reaction

  2. Calculate the moles of each reactant

  3. Compare the moles & deduce the limiting reactant