CI - Rates and Order

Question 1

explain the term rate of reaction?

Answer 1

it is the speed at which a chemical reaction takes place

Question 2

what are factors effecting the rate?

Answer 2

• conc. of solution
• surface area of solid
• preassure of gasses
• temp
• catalyst

Question 3

how do you use a graph to calculate the rate of a reaction?

Answer 3

draw a tangent on the line at any point and calculate the gradient
rise over run

Question 4

explain the term order of reaction:

Answer 4

order of reaction with respect to (wrt) to a given reactant is the power to which the conc of the reactant is raised in the rate equation

Question 5

what types of order are there?

Answer 5

first
second
zero

Question 6

what is first order?

Answer 6

when conc doubles so does the rate
reaction rate is proportional to [A]

rising strait line on graph
unit of k = s-1

Question 7

what is second order?

Answer 7

if conc doubles rate will quadruple
reaction rate is proportional to [A]^2

upwards curve on graph
unit of k = dm3 mol-1 s-1

Question 8

what is zero order?

Answer 8

rate is not affected by any changes in [A]

horizontal line on graph
unit of k = mol dm-3 s-1

Question 9

what is K?

Answer 9

k = rate constant (diff for diff reactions)

Question 10

what affects the value of k?

Answer 10

only temp affects its value
it increases with temp

Question 11

what is the rate determining step?

Answer 11

this is the slowest step of the reaction

Question 12

what is the initial rate?

Answer 12

the rate at the beginning of a reaction
it can b efound by drawing a tangent at the point t=0 and measuring its gradient

Question 13

how can you measure the rate of reaction?

Answer 13

• measure vol of gas evolved
• change in pH
• measuring mass change
• colourimetry
• chem analysis (titration and quenching)