Measuring Rates of Reaction: Changes in Mass

Changes in Mass

Definition:

• Measuring the rate of a chemical reaction involves observing how quickly reactants transform into products.

Importance:

• Essential for understanding reaction speed.
• Crucial in industrial processes and laboratory experiments.

Changes in Volume:

• Another way to measure the rate is by monitoring changes in mass.

Example:

• Consider a reaction where a solid substance A turns into a gas B.

• At the start, we have 10 grams of A.

• After 5 minutes, we found 8 grams of A remaining.

• The change in mass of A is 10 g - 8 g = 2 g.

• The time taken is 5 minutes, which is 300 seconds.

• Rate of reaction = $\frac{\text{Change in mass of A}}{\text{Time}}$ = $\frac{2 \text{ g}}{300 \text{ s}}$ = 0.0067 $\frac{\text{g}}{\text{s}}$

Units:

• Rate of reaction is measured in cubic centimetres per second (cm³).
• It indicates how many cubic centimetres of gas disappear or form per second.