Rates of Reaction

Question 1

What is the rate of a chemical reaction?

Answer 1

how fast the reactants are changed into products

Question 2

What are some slow chemical reactions?

Answer 2

The rusting of iron and chemical weathering.

Question 3

What’s an example of a moderate speed chemical reaction?

Answer 3

Magnesium reacting with an acid to produce a gentle stream of bubbles

Question 4

What’s an example of a fast chemical reaction?

Answer 4

Burning and explosions

Question 5

How can you tell which Reaction has a faster rate on a graph?

Answer 5

The steeper the line on the graph, the faster the rate of reaction.

Question 6

What happens to the graph of a chemical reaction over time?

Answer 6

Overtime the graph becomes less steep as the reactants are used up.

Question 7

What is one way of measuring the rate of reaction?

Answer 7

(Quantity of reactant used) ÷ (time taken)

Question 8

What is another way of measuring the rate of reaction?

Answer 8

(Quantity of product formed) ÷ (time taken)

Question 9

What are the units for the rate of reaction?

Answer 9

cm^3/s or g/s or mol/s

Question 10

What is meant by the collision frequency of reacting particles?

Answer 10

how often they collide

Question 11

What is the minimum amount of energy the particles need to react?

Answer 11

Activation energy

Question 12

Why do particles need the activation energy?

Answer 12

To break the bonds in the reactants and start the reaction

Question 13

What do more frequent collisions mean for the reaction?

Answer 13

It’s faster

Question 14

How do certain factor increase the rate of reaction?

Answer 14

They increase the number of collisions or the amount of energy particles collide with. Therefore, increasing the number of SUCCESSFUL collisions

Question 15

How many factors affect the rate of reaction?

Answer 15

5

Question 16

What are the 4 factors that affect the rate of reaction?

Answer 16

1.Temperature
2.Concentration of a solution
3.Pressure of gas
4.Surface area
5.A catalyst

Question 17

How does increasing the temperature increase the rate?

Answer 17

1. when the temperature is increased, the particles move faster
2. If they move faster they’ll collide more frequently
3. The faster they move, the more energy they will have so more of the collisions will have enough energy to make the reaction happen.
   Therefore more successful collisions take place

Question 18

How does increasing the concentration increase the rate?

Answer 18

1. I fa solution is made more concentrated, it means there’re more particles moving in the same volume of solvent
2. This makes makes collisions between the reactant particles more frequent.
   Therefore, there are more successful collisions likely to take place.

Question 19

How does increasing the pressure increase the rate?

Answer 19

1. When the pressure of a gas is increased it means the same number of particles occupy a smaller space
2. This makes collisions between reactant particles more frequent Therefore resulting in more successful collisions.

Question 20

How does increasing surface area increase the rate of reaction?

Answer 20

1. Breaking up a solid into smaller pieces increases the surface area:volume ratio
2. So, for the same volume of solid the particles around it will have more area to work on so there’ll be more frequent collisions.
   Therefore, there’ll be a higher likelihood of successful collisions taking place.

Question 21

What does a catalyst do?

Answer 21

It speeds up a reaction without being used up in the reaction itself–> so it’s not part of the overall reaction equation itself

Question 22

How does using a catalyst increase the rate of reaction?

Answer 22

1. Catalysts work by decreasing the activation energy needed for the reaction to occur.
2. They do this by, providing an alternative pathway with a lower activation energy.