Rates

Question 1

describe how the initial rate of reaction can be determined from a graph of volume of gas produced over time

Answer 1

draw a tangent on the graph and determine a gradient

Question 2

whats is meant by the term order of reaction with respect to A

Answer 2

power of concentration in a rate equation e.g [X]* *=order

Question 3

whats the additional point on a graph

Answer 3

adding the origin (0,0)

Question 4

effect of temp on rate required practical of thiosulfate and HCl (7 points)

Answer 4

-place known volume and concen of thiosulfate in a conical flask
-place known volume and concen of HCl in boiling tube
-warm both to required temperature in a water bath
-place conical flask on top of a cross add HCl and start stopwatch
-stop timing when cross is no longer visible
-repeat for at least 5 diff temps
-find rate by calculating time
-plot temp a-axis rate y-axis

Question 5

series of experiments were carried out using concen of X approx 100 times Z suggest the rate equation under these conditions

Answer 5

[X] is so big it’s effectively constant therefore the order is 0 for it

Question 6

why are initial rates used to determine these orders rather than the rates of reaction at other times

Answer 6

bc the initial concens are known

Question 8

Explain qualitatively why doubling the temperature has much greater effect on the rate of the reaction than doubling the concentration of E

Answer 8

Doubling the temperature causes Many more particles to have more than or equal activation energy

More successful collisions per unit time

Whereas doubling E only doubles the number within this E