Chemistry Paper 2 JUNE 2023 Questions
with Answers Latest Update
1. what is an example of a reaction at a slow rate? - Correct Answer iron rusting
2. what is an example of a moderate speed reaction? - Correct Answer Metal
magnesium reacting with an acid to produce a gentle stream of bubbles
3. what is an example of a fast reaction? - Correct Answer burning
4. explosions
5. What does the rate of reaction depend on? - Correct Answer the frequency of
collisions between particles.
6. the energy with which particles collide: the energy transferred during a collision
7. What is activation energy? - Correct Answer the minimum amount of energy
needed to start a chemical reaction
8. what 4 things increase rates of reaction? - Correct Answer temperature -
concentration/pressure - surface area - catalyst
9. how does a higher temperature increase reaction rate? - Correct Answer - when
t increased the particles have more energy and move faster
- they collide more frequently
- more collisions have enough energy to make the reaction happen (have
minimum Enact)
10. How does conk/pressure affect rate of reaction? - Correct Answer CONC - there
are more particles in the same volume of solvent
11. PRESSURE - same number of particles in a smaller space
both make collisions between the reactant particles more frequent
12. How does increasing the surface area increase the rate of reaction? - Correct
Answer surface area to volume ratio - same volume but more area to work on -
more frequent collisions
13. How does a catalyst increase the rate of a reaction? - Correct Answer - speeds
up reaction without being used up
- decrease the activation energy needed for the reaction to occur : by
providing an alternative reaction pathway with a lower activation energy
,14. what 3 ways can you carry out the rates of reaction practical? - Correct Answer
precipitation & colour change
- change in mass
- volume of a gas given off
15. what is the rate of reaction equation? - Correct Answer Rate of reaction =
Amount of reactant used or amount of product formed / Time
16. summaries how you can measure rate of reaction with colour change - Correct
Answer - initial solution is transparent and forms a cloudy precipitate that
becomes opaque
- you can put a mark underneath a conical flask (e.g. an X)
- faster the mark disappears, the quicker the reaction
- very subjective results - not so good. can't plot a rate of reaction graph
17. summaries how you can measure rate of reaction with change in mass? -
Correct Answer - a reaction that produces a gas - a mass balance - a stopwatch
- a cotton bung (to prevent acid spraying out)
- quicker the reading on the balance drops the faster the rate of reaction
- take readings at regular intervals and plot a graph
- MOST ACCURATE - releases gas straight into room, could be peligroso
18. summaries how you can measure rate of reaction with the volume of gas given
off - Correct Answer - use a gas syringe to measure the volume gas given off
- more gas given off during a time interval, faster the reaction
- usually give volumes to nearest cm3, white accurate and can plot a graph.
if the reaction is too vigorous it could blow the end out of the syringe
19. how do you do the actual mass change practical? - Correct Answer magnesium
and HCl produce hydrogen
- add a set volume of dilute HCl to a conical flask and put onto a mass
- add magnesium ribbon and plug with cotton wool (prevent acid spraying
out)
- start stopwatch and record initial mass
- take readings at regular intervals (every 10 sacs e.g. )
- plot results with time on x and mass lots on y
- repeat with more concentrated acid solutions
- keep mg ribbon the same and volume of acid
20. how do you do the actual colour change practical? - Correct Answer sodium
thiosulfate and HCl produce cloudy precipitate
- both start clear solutions form yellow precipitate sulfur
- place flask on piece of paper with a black x drawn on it, add a set volume
of dilute sodium thiosulfate
- add dilute HCl and start the timer
- time how long it takes for X to disappear
, - repeat with different cons of 1 reactant
- volumes must stay the same
- doesn't give a set of graphs, make a table with conk of HCl against time
taken
21. what happens when reactants react? - Correct Answer their concentrations fall -
so forward reaction slows down
- as more products are made and their conks rise the backward reaction
speeds up
22. what happens when a system is at equilibrium and how does it get there? -
Correct Answer forward reaction going at the same rate as backwards reaction
23. reactants react to form products - after their cons rise they react backwards
24. what happens at equilibrium and when can it happen? - Correct Answer
CLOSED SYSTEM
- both reactions are still happening but there is no overall effect (dynamic
equilibrium), concentrations of reactants and products have reached a
balance and won't change
25. where can the position of equilibrium be and what does it mean? - Correct
Answer to the right - conk of products greater than reactants
26. to the left - conk of reactants greater than products
27. what does position of equilibrium depend on? - Correct Answer temperature,
pressure(only if reaction involves gases), concentration
28. What is Le Hotelier’s principle? - Correct Answer The idea that if you change
the conditions of a reversible reaction at equilibrium, the system will try to
counteract that change
29. What does Le Hotelier’s Principle mean in terms of decreasing temperature? -
Correct Answer if you decrease the temperature, equilibrium will move in
exothermic direction to produce more temp..... MORE products for
EXOTHERMIC reaction and FEWER products for ENDOTHERMIC reaction
30. What does Le Hotelier’s Principle mean in terms of increasing temperature? -
Correct Answer if you raise the temp equilibrium moves in endothermic direction
- more products for endothermic reaction and fewer for exothermic reaction
31. what does Le Chat mean intern of pressure - Correct Answer (only reactions
involving gases)
- increase pressure - equilibrium moves in direction of fewer molecules of
gas to reduce it (balloons)
- decrease pressure - equilibrium moves in direction of more molecules of
gas
with Answers Latest Update
1. what is an example of a reaction at a slow rate? - Correct Answer iron rusting
2. what is an example of a moderate speed reaction? - Correct Answer Metal
magnesium reacting with an acid to produce a gentle stream of bubbles
3. what is an example of a fast reaction? - Correct Answer burning
4. explosions
5. What does the rate of reaction depend on? - Correct Answer the frequency of
collisions between particles.
6. the energy with which particles collide: the energy transferred during a collision
7. What is activation energy? - Correct Answer the minimum amount of energy
needed to start a chemical reaction
8. what 4 things increase rates of reaction? - Correct Answer temperature -
concentration/pressure - surface area - catalyst
9. how does a higher temperature increase reaction rate? - Correct Answer - when
t increased the particles have more energy and move faster
- they collide more frequently
- more collisions have enough energy to make the reaction happen (have
minimum Enact)
10. How does conk/pressure affect rate of reaction? - Correct Answer CONC - there
are more particles in the same volume of solvent
11. PRESSURE - same number of particles in a smaller space
both make collisions between the reactant particles more frequent
12. How does increasing the surface area increase the rate of reaction? - Correct
Answer surface area to volume ratio - same volume but more area to work on -
more frequent collisions
13. How does a catalyst increase the rate of a reaction? - Correct Answer - speeds
up reaction without being used up
- decrease the activation energy needed for the reaction to occur : by
providing an alternative reaction pathway with a lower activation energy
,14. what 3 ways can you carry out the rates of reaction practical? - Correct Answer
precipitation & colour change
- change in mass
- volume of a gas given off
15. what is the rate of reaction equation? - Correct Answer Rate of reaction =
Amount of reactant used or amount of product formed / Time
16. summaries how you can measure rate of reaction with colour change - Correct
Answer - initial solution is transparent and forms a cloudy precipitate that
becomes opaque
- you can put a mark underneath a conical flask (e.g. an X)
- faster the mark disappears, the quicker the reaction
- very subjective results - not so good. can't plot a rate of reaction graph
17. summaries how you can measure rate of reaction with change in mass? -
Correct Answer - a reaction that produces a gas - a mass balance - a stopwatch
- a cotton bung (to prevent acid spraying out)
- quicker the reading on the balance drops the faster the rate of reaction
- take readings at regular intervals and plot a graph
- MOST ACCURATE - releases gas straight into room, could be peligroso
18. summaries how you can measure rate of reaction with the volume of gas given
off - Correct Answer - use a gas syringe to measure the volume gas given off
- more gas given off during a time interval, faster the reaction
- usually give volumes to nearest cm3, white accurate and can plot a graph.
if the reaction is too vigorous it could blow the end out of the syringe
19. how do you do the actual mass change practical? - Correct Answer magnesium
and HCl produce hydrogen
- add a set volume of dilute HCl to a conical flask and put onto a mass
- add magnesium ribbon and plug with cotton wool (prevent acid spraying
out)
- start stopwatch and record initial mass
- take readings at regular intervals (every 10 sacs e.g. )
- plot results with time on x and mass lots on y
- repeat with more concentrated acid solutions
- keep mg ribbon the same and volume of acid
20. how do you do the actual colour change practical? - Correct Answer sodium
thiosulfate and HCl produce cloudy precipitate
- both start clear solutions form yellow precipitate sulfur
- place flask on piece of paper with a black x drawn on it, add a set volume
of dilute sodium thiosulfate
- add dilute HCl and start the timer
- time how long it takes for X to disappear
, - repeat with different cons of 1 reactant
- volumes must stay the same
- doesn't give a set of graphs, make a table with conk of HCl against time
taken
21. what happens when reactants react? - Correct Answer their concentrations fall -
so forward reaction slows down
- as more products are made and their conks rise the backward reaction
speeds up
22. what happens when a system is at equilibrium and how does it get there? -
Correct Answer forward reaction going at the same rate as backwards reaction
23. reactants react to form products - after their cons rise they react backwards
24. what happens at equilibrium and when can it happen? - Correct Answer
CLOSED SYSTEM
- both reactions are still happening but there is no overall effect (dynamic
equilibrium), concentrations of reactants and products have reached a
balance and won't change
25. where can the position of equilibrium be and what does it mean? - Correct
Answer to the right - conk of products greater than reactants
26. to the left - conk of reactants greater than products
27. what does position of equilibrium depend on? - Correct Answer temperature,
pressure(only if reaction involves gases), concentration
28. What is Le Hotelier’s principle? - Correct Answer The idea that if you change
the conditions of a reversible reaction at equilibrium, the system will try to
counteract that change
29. What does Le Hotelier’s Principle mean in terms of decreasing temperature? -
Correct Answer if you decrease the temperature, equilibrium will move in
exothermic direction to produce more temp..... MORE products for
EXOTHERMIC reaction and FEWER products for ENDOTHERMIC reaction
30. What does Le Hotelier’s Principle mean in terms of increasing temperature? -
Correct Answer if you raise the temp equilibrium moves in endothermic direction
- more products for endothermic reaction and fewer for exothermic reaction
31. what does Le Chat mean intern of pressure - Correct Answer (only reactions
involving gases)
- increase pressure - equilibrium moves in direction of fewer molecules of
gas to reduce it (balloons)
- decrease pressure - equilibrium moves in direction of more molecules of
gas
