Rates Of Reaction

Question 1

What is Activation energy? (2)

Answer 1

• The minimum amount of energy
• required for a reaction to occur

Question 2

In terms of particles, how does Temperature affect the rate of a reaction? (6)

Answer 2

• increased temperature increases rate of reaction
• particles gain kinetic energy
• particles move faster
• more chance of collisions
• resulting in more successful collisions (enough activation energy)
• in a given time

Question 3

In terms of particles, how does concentration affect the rate of a reaction? (5)

Answer 3

• increased concentration increases rate of reaction
• more acid particles in the same volume
• more chance of collisions
• resulting in more successful collisions
• in a given time

Question 4

In terms of particles, how does surface area affect the rate of a reaction? (5)

Answer 4

• increased surface area increases rate of reaction
• more particles on the surface exposed to the other reactant
• more chance of collisions
• resulting in more successful collisions
• in a given time

Question 5

What is activation energy (2)

Answer 5

• The minimum amount of energy required
• For reaction to happen

Question 6

What is a catalyst (2)

Answer 6

• Substance that speeds up the rate of a chemical reaction
• without being used up

Question 7

How do catalysts work? (2)

Answer 7

• They provide an alternate reaction pathway
• with lower activation energy

Question 8

How does pressure increase the rate of a reaction? (2)

Answer 8

• More particles in a smaller volume
• More frequent collisions

Question 9

What is gas pressure?

Answer 9

the force that the gas exerts on the walls of its container

Question 10

What is the formula for rate?

Answer 10

1 / time

Question 11

How can you see the rate of a reaction from a graph?

Answer 11

Steeper gradient - faster rate

Question 12

What is the catalyst for hydrogen peroxide?

Answer 12

Manganese dioxide
(Or Manganese(IV) oxide)

Question 13

why is cotton wool put on the top of a conical flask in the reaction between CaCO₃ and HCl?

Answer 13

To avoid loss of mass by spray

Question 14

What is the balanced symbol equation for the reaction between CaCO₃ and HCl

Answer 14

CaCO₃ + 2HCl —> CaCl₂ + H₂O + CO₂

Question 15

How can you increase the rate of the reaction between CaCO₃ and HCl

(3)

Answer 15

• increase the surface area of the CaCO₃ (limestone/marble chips)
• increase the concentration of the acid
• increase the temperature

Question 16

What is the balanced symbol equation for the decomposition of hydrogen peroxide?

Answer 16

2H₂O₂ —> 2H₂O + O₂