• The rate of a reaction can be determined by following the
formation of a product over time:
𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑝𝑟𝑜𝑑𝑢𝑐𝑡
𝑟𝑎𝑡𝑒 =
𝑡𝑖𝑚𝑒
Unit of rate is 𝑚𝑜𝑙 𝑑𝑚−3 𝑠 −1 .
• Rate of reaction can be followed using various monitoring
methods:
1. Volume of gas evolved.
2. Change in mass.
3. Change in intensity of colour (colorimetry).
4. Change in concentration of product or reactant through
titration.
5. Change in pH of a solution.
6. Electrical Conductivity.
• A first order rate equation is where rate is directly proportional
to concentration. This can be expressed as:
𝑅𝑎𝑡𝑒 = 𝑘[𝐴]
where 𝑘 is the proportionality (rate) constant.
• A second order rate equation is when the concentration is
doubled, the rate increases by a factor of four: