Reaction Rates 3.2.2

Question 1

What is meant by rate of reaction?

Answer 1

Rate of chemical reaction measures how fast a reactant is being used up or how fast a product is being formed

Question 2

What can rate of reaction be defined as?

Answer 2

The rate of a chemical reaction can be defined as the change in concentration of a reactant or a product in a given time

Question 3

What is the formula involving rate of reaction, change in concentration and time?

Answer 3

Rate= change in conc./ time

Question 4

What are the units for conc?

Answer 4

moldm-3

Question 5

Unit for time?

Answer 5

S

Question 6

Unit for rate of reaction?

Answer 6

moldm-3 s-1

Question 7

When is the rate of reaction the fastest and why?

Answer 7

Fastest at the start of the reaction as each reactant is at its highest concentration

Question 8

When does the rate of reaction slow down? Why?

Answer 8

The rate of reaction slows down as the reaction proceeds, because the reactants are being used up and their concentrations decrease

Question 9

When is the rate of reaction zero?

Answer 9

Once one of the reactants has been completely used up, the concentration stops changing and the rate of reaction is zero

Question 10

What happens to the concentration once one of the reactants has been used up ?

Answer 10

the concentration stops changing and the rate of reaction is zero

Question 11

What can be used to monitor the rate of a chemical reaction?

Answer 11

Concentration- time graphs

Question 12

In terms of a concentration time graph explain the rate of a chemical reaction at the start, middle and end.

Answer 12

Slope of the curve is steepest at the start of the reaction, when the rate is greatest

Curve becomes less steep as the reaction proceeds

Eventually the curve becomes a straight line parallel to the x-axis when the reaction is complete and the rate is zero