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Home > Chemistry > Calculations > Calculations based on reactions


Calculations based on reactions


All data used in calculations is taken from the SQA Chemistry Data Booklet - Standard Grade and Intermediate 2.

Using Balanced Equations (Credit)

The balanced equation for a chemical reaction can be used to calculate:

  1. the mass of product formed (given the mass of reactants used)
  2. the mass of reactants used (given the mass of product formed)

The Gram Formula Mass (GFM) is calculated by adding together the relative atomic masses of all the atoms or ions in the formula of the substance.

The calculation of moles and mass can be done using the equations,

moles = {mass \over GFM}and mass = moles \times GFM

This video explains how to work out a balanced equation for a chemical reaction.

Video: Balancing chemical equations

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