16

Question 1

give the two concentration rate equations

Answer 1

rate = change in conc of product/time
rate = change in conc of reactant/time

Question 2

how can you measure rate of reaction

Answer 2

measuring the volume of gas evolved
measuring change in mass
colorimetry
change in conc using titration
measuring change in pH
measuring change in electrical conductivity

Question 3

how do you measure the volume of gas evolved

Answer 3

collect using gas syringe
collect through water with measuring cylinder

Question 4

what is quenching a reaction

Answer 4

the process of stopping or slowing down the reaction in an aliquot

Question 5

what is the relationship between concentration of reactant & rate of reaction

Answer 5

directly proportionate

Question 6

what are the rate equations for 0 order, 1st order & 2nd order

Answer 6

rate = k
rate = k[A]
rate = k[A]*2

Question 7

what effects rate constants

Answer 7

temperature

Question 8

give a third order rate equation

Answer 8

rate = k[A]*2[B]

Question 9

what is a rate equation

Answer 9

an equation expressing the mathematical relationship between the rate of reaction and the concentration of the reactants

Question 10

what is the RDS (rate determining step)

Answer 10

the slowest step in the mechanism for the reaction

Question 11

how do you calculate the order of a reaction from a conc time graph

Answer 11

find the half life of the reactant if its the same its first order if it doubles each time its second order if its a straight line with a negative gradient its 0 order

Question 12

how do you calculate rate of reaction on a conc or volume time graph

Answer 12

drawing a tangent to line & calculating its gradient

Question 13

what is a reaction that is elementary

Answer 13

a reaction taking place that is a single collision between two reactant particles

Question 14

define activation energy

Answer 14

the minimum energy that particles must have for a reaction to occur

Question 15

define catalyst

Answer 15

a substance that increases the rate of reaction but is chemically unchanged at the end of the reaction

Question 16

what is a homogeneous catalyst

Answer 16

a catalyst in the same phase as the reactants

Question 17

what is a heterogeneous catalyst

Answer 17

a catalyst in a different phase to that of the reactant

Question 18

explain the 3 key steps in a catalyzed reaction

Answer 18

1 adsorption - reactants are adsorbed into the surface of the catalyst
2 reaction - reactants are held in position to react
3 desorption - the product molecules leave the surface of the catalyst

Question 19

what is an anticatalyst

Answer 19

the reaction is catalysed by one of its products

Question 20

why does rate of reaction increase as temperature increases

Answer 20

increased proportion of collisions have activation energy
increased frequency of collisions as particles have more kinetic energy

Question 21

what is the Arrhenius equation

Answer 21

k = Ae*-Ea/RT