C6

Question 1

How do you calculate the rate of reaction?

Answer 1

• quantity of reactants used/ time taken
• quantity of products formed/ time
  taken

Question 2

What four factors affect the rate of reaction?

Answer 2

1. temperature
2. concentration/pressure
3. surface area
4. catalyst

Question 3

Explain collision theory

Answer 3

In order for particles to react, they have to collide with each other with sufficient energy (activation energy)

Question 4

How does temperature affect the rate of chemical reactions?

Answer 4

• Particles gain more kinetic energy and move faster
• This faster movement allows the particles to collide more frequently
• The additional energy means that there are more frequent SUCCESSFUL collisions

Question 5

How does concentration/ pressure affect the rate of chemical reaction?

Answer 5

if there are more particles per unit of volume, there are more frequent successful collisions

Question 6

How does the surface area affect the rate of chemical reaction?

Answer 6

• a higher surface area to volume ratio provides a greater area for the collisions to take place
• higher frequency of successful collisions

Question 7

How does the presence of a catalyst affect the rate of chemical reaction?

Answer 7

Catalysts lower the activation energy which means there are more frequent successful collisions

Question 8

What happens when the equilibrium lies to the right?

Answer 8

when the concentration of products is greater than the reactants

Question 9

What happens when the equilibrium lies to the left?

Answer 9

The concentration of the reactants is greater

Question 10

What is Le Chatelier’s Princriple?

Answer 10

states that if you change the conditions of a reversible reaction at equilibrium in a closed system, the system will try to counteract the change

Question 11

How does temperature effect the equilibrium?

Answer 11

• if you decrease the temp, the equilibrium will move in the exothermic direction to produce more heat
  • more products for the exothermic reaction
• if you raise the temp, the equilibrium will move in the endothermic direction to try and decrease it
  • more products for the endothermic reaction (fewer products for the exothermic reaction)

Question 12

How does pressure effect the equilibrium?

Answer 12

only affects an equilibrium involving gases

• if you increase the pressure, the equilibrium tries to reduce it by moving the equilibrium in the direction where there are fewer molecules
• if you decrease the pressure, equilibrium moves in the direction where there are more molecules of gas

Question 13

How does concentration effect the equilibrium?

Answer 13

• increasing the concentration of the reactants, makes more product
• decreasing the concentration of the products, reduces the amount of the reactants