Calculating Rates of Reactions Flashcards

All 6 cards in this deck

What two things can be measured over time to find the rate of a chemical reaction?

The quantity of a reactant used up, or the quantity of a product formed.

What units are used for rate of reaction when the quantity is measured as a mass or as a gas volume?

g/s (mass) or cm$^3$/s (volume).

What are the steps to calculate the mean rate of a reaction?
e.g. 48 cm$^3$ of gas collected in 60 s

1. Find the change in quantity of product: $48$ cm$^3$
2. Divide by the time taken: $48 \div 60$
3. Mean rate $= 0.8$ cm$^3$/s

Name three experimental methods used to follow the rate of a reaction.

Measuring the volume of gas produced, measuring the loss in mass, and following a colour change or turbidity (cloudiness).

In a 'loss of mass' rate experiment, why does the mass of the flask and contents decrease?

A gas is produced which escapes from the flask.

True or false? The mean rate of a reaction is the same as the rate at every moment of the reaction.

False. The mean rate is an average; the actual rate is fastest at the start and slows as reactants are used up.