unit 6.2 - rate of reaction

Question 1

what is the effect on the rate of reaction of changing the concentration of solutions?

Answer 1

If concentration increases, there are more particles. So, collisions happen more often, leading to the frequency of collisions increasing. This makes the rate of reaction increase.

Question 2

what is the effect on the rate of reaction of changing the pressure of gases?

Answer 2

If pressure is increased, the frequency of collisions increases, so the rate of reaction increases

Question 3

what is the effect on the rate of reaction of changing the surface area of solids

Answer 3

If the surface area increases, the frequency of collisions increases, so the rate of reaction increases

Question 4

what is the effect on the rate of reaction of changing the temperature?

Answer 4

If the temperature increases, Kinetic and Technical energy (TE changes to KE) increases so the particles have more energy so they move faster, leading to the frequency of collisions increasing. So, the rate of reaction increases

Question 5

what is the effect on the rate of reaction of adding or removing a catalyst?

Answer 5

whena catalyst is added, they provide alternate routes which have lower energy required (lower activation energy), so the rate of reaction increases

Question 6

What does a catalyst do?

Answer 6

increase the rate of reaction and is unchanged at the end of a reaction

Question 7

when does a successful collision happen?

Answer 7

-particles have enough energy (activation energy)
-particles must collide

Question 8

what is rate of reaction?

Answer 8

how fast something happens
–> how quickly everything reacts
–> how often theres a successful collision

Question 9

rate of reaction depends on 2 things. what are they?

Answer 9

-frequency of collisions
-energy of the collision

Question 10

what are the 5 factors that affect the rate of reaction?

Answer 10

-concentration (density) [solutions]
-surface area [solids]
-temperature
-pressure [gases]
-catalysts

Question 11

if temperature decreases and catalysts are added, what happens to the energy?

Answer 11

decreases

Question 12

if concentration/pressure/surface area decreases, what happens to the energy?

Answer 12

stays the same

Question 13

if concentration/pressure/surface area/temperature decreases, what happens to the frequency of collisions?

Answer 13

decreases

Question 14

if catalysts are added, what happens to the frequency of collisions?

Answer 14

stays the same

Question 15

if concentration/pressure/surface area/temperature decreases, what happens to the rate of reaction?

Answer 15

decreases

Question 16

if catalyst are added, what happens to the rate of reaction?

Answer 16

increases

Question 17

where do the reactants get their energy from?

Answer 17

around them (take thermal energy)

Question 18

give 2 practical methods for investigating the rate of a reaction

Answer 18

-change in mass of a reactant/product
-formation of a gas

Question 19

how can the rate of reaction be measured?

Answer 19

gas produced, mass of reactants, pH, colour change, light transmitted