7.3 - Application of Factors that Affect the Rate of Reaction in Daily Life

Size of Reactants

Antacid tablets: Chewing a tablet breaks it into smaller pieces, increases its exposed surface area and speeds up its reaction with stomach acid.
Cooking potatoes: Thin slices or long strips expose a greater total surface area to hot cooking oil and cook faster than an uncut potato.
Burning coal: Small fragments have a larger exposed surface area and burn faster.

Acid-rain corrosion: Industrial air may contain a high concentration of sulphur dioxide. A higher concentration of acidic pollutants increases rain acidity and accelerates corrosion of nearby iron structures.
Car engines: Petrol vapour and air are compressed in the combustion chamber. Compression increases petrol-vapour concentration, allowing very rapid combustion; the released energy moves the car.

Cleaning: Detergent powder and hot water combine chemical action with higher temperature, so washing proceeds faster.
Cooking: Higher temperature cooks food faster. Water boils at $100^{\circ} C$ , whereas cooking oil has not yet boiled even at $180^{\circ} C$ , so frying cooks food rapidly.
Food preservation: Refrigeration lowers temperature and slows the growth of bacteria that spoil food.
Pressure cooker: The higher operating temperature speeds up cooking.

Catalytic converter: Platinum catalyses the conversion of unburned hydrocarbons, carbon monoxide and nitrogen oxides in car exhaust into safer products such as carbon dioxide, water and nitrogen.
Alcohol production: Enzymes in yeast catalyse the fermentation of glucose to ethanol at $37^{\circ} C$ . Fermentation is also used in making tapai.

Increase rate when a process should finish quickly: cut food or fuel into smaller pieces, raise temperature, increase concentration or pressure when suitable, or use a catalyst.
Decrease rate when deterioration should be slowed: lower temperature, as in refrigerated food storage.