7.2.2 Total Surface Area
Total Surface Area
- For reaction involves solid reactant, when the solid reactants is broken up into smaller pieces, the total surface area of the reactant becomes bigger.
- The bigger the total surface area of the reactant, the higher the rate of reaction.
- The smaller the size of the particle, the bigger the total surface area.
- The bigger the total surface area, the higher the rate of reaction.
Experiment
The reaction between hydrochloric acid, HCl and calcium carbonate, CaCO3.
Experiment 2
The reaction between hydrochloric acid, HCl and calcium carbonate, CaCO3.
CaCO3 +2HCl→ CaCl2 +CO2 + H2O
Experiment 1
25 cm3 of 0.5 mol dm–3 hydrochloric acid + calcium carbonate chips. The carbon dioxide gas released is collected in a burrete. The volume of the gas released is recorded in every 30s. The result is plotted in a graph.
Experiment 2
25 cm3 of 0.5 mol dm–3 hydrochloric acid + calcium carbonate powder. As in experiment 1, the carbon dioxide gas released is collected in a burette and the volume of the gas released is recorded in every 30s. The result is plotted in the same graph in experiment 1.
Conclusion
- The gradient of the curve for experiment 2 is greater than the curve for experiment 1. This indicates that the rate of reaction in experiment 2 is higher than experiment 1.
- We can conclude that the smaller the particle size of the reactant, the bigger the total surface area, and the bigger the total surface area, the higher the rate of the reaction will be.