Rates of Reaction / Reversible Reactions

Question 1

What is the rate of a reaction? - Rates of Reaction

Answer 1

A measure of how quickly a reactant is used up or how quickly a product is formed

Question 2

What is collision theory? - Rates of Reaction

Answer 2

The theory that for a chemical reaction to happen reactant particles must collide with each other and the particles must have enough energy to react

Question 3

What is a successful collision? - Rates of Reaction

Answer 3

A collision between reactant particles that has enough energy to create a reaction

Question 4

What importance is activation energy for successful reactions? - Rates of Reaction

Answer 4

If particles do not have sufficient activation energy (the minimum amount of energy that colliding particles must have in order to react) a reaction won’t take place

Question 5

What 2 ways can be used to calculate the mean rate of a reaction? What unit is used - Rates of Reaction

Answer 5

Rate of reaction = quantity of reactant used / time taken
OR quantity of product formed / time taken
Units in g/s or g/minute

Question 6

How can the volume of gas produced in a reaction be measured? - Rates of Reaction

Answer 6

A gas syringe can be placed in a bung on a conical flask and it will measure the volume of gas produced

Question 7

How can the gradient of a rate of reaction graph be useful to us? - Rates of Reaction

Answer 7

The gradient of the line shows the rate of reaction (steep gradient = quick reaction)

Question 8

How does the concentration of reactants affect the rate of reaction? - Rates of Reaction

Answer 8

The reactant particles become more crowded as there are more of them, which increases the frequency of successful collisions and increases the rate of a reaction

Question 9

How does the pressure of reactants (gas) affect the rate of reaction? - Rates of Reaction

Answer 9

By increasing the pressure, reactant particles become more crowded, increasing the frequency of successful collisions, and increasing the rate of reaction

Question 10

How can you calculate the rate of a reaction at a given stage of the reaction? - Rates of Reaction

Answer 10

By drawing a tangent to the curve on the graph, calculate the gradient of this tangent to find the rate of the reaction

Question 11

How does surface area : volume ratio affect the rate of a reaction? - Rates of Reaction

Answer 11

The higher the surface area to volume ratio, more reactant particles are exposed at the surface. This means that the frequency of successful collisions between reactants increases, increasing the rate of reaction

Question 12

How does temperature affect the rate of a reaction? - Rates of Reaction

Answer 12

It increases the internal (kinetic) energy of the particles, meaning more particles have activation energy, meaning the number of successful collisions increases. Rate increases.

Question 13

What is a catalyst? - Rates of Reaction

Answer 13

A substance that increases the rate of a chemical reaction without being used up

Question 14

How do catalysts work? - Rates of Reaction

Answer 14

Provides an alternative reaction pathway with a lower activation energy. Increases the frequency of successful collisions

Question 15

How do a catalysts effects appear on a reaction profile? - Rates of Reaction

Answer 15

The activation energy is lower than previously, therefore the gradient of the loop on the graph is smaller

Question 16

What is a reversible reaction? - Reversible Reactions

Answer 16

A reaction where the reactants can be converted into products and products back into reactants

Question 17

What rule is there for reversible reactions regarding endothermic and exothermic reactions? - Reversible Reactions

Answer 17

If a reaction is endothermic one direction, then it is exothermic in the other

Question 18

Which direction is the equilibrium of a forward and backward reaction? - Reversible Reactions

Answer 18

The forward reaction goes to the right

The backward reaction goes to the left

Question 19

How does a reversible reaction work in terms of hydrated copper sulfate? - Reversible Reactions

Answer 19

As the hydrated copper sulfate is heated, the water molecules are driven off, leaving ANHYDROUS copper sulfate. By adding water, the copper sulfate becomes hydrated again

Question 20

What is an equilibrium? - Reversible Reactions

Answer 20

A state where the forward and backward reactions are happening at the same rate, with the concentrations of all reactants being constant

Question 21

What is dynamic equilibrium? - Reversible Reactions

Answer 21

A state of balance between continuing processes

Question 22

Describe the Haber process - Reversible Reactions

Answer 22

Nitrogen gas is reacted with hydrogen gas to make ammonia gas. The forward reaction is exothermic

Question 23

What is Le Chatelier’s principle? - Reversible Reactions

Answer 23

The idea that if the conditions of a reversible reaction are altered, the equilibrium will shift to oppose the change

Question 24

How can the reaction conditions be changed in a reversible reaction? - Reversible Reactions

Answer 24

Changing the PRESSURE
Changing the CONCENTRATION
Changing the TEMPERATURE

Question 25

When a change is made to a system at equilibrium, what does the equilibrium do? - Reversible Reactions

Answer 25

The equilibrium position changes to oppose the change made

Question 26

Name an example of the equilibrium opposing a change - Reversible Reactions

Answer 26

If the temperature of a reaction is increased, the position of the equilibrium will shift to the endothermic direction to reduce the temperature

Question 27

If pressure is increased in a reaction involving gases, what happens to the equilibrium? - Reversible Reactions

Answer 27

The equilibrium will shift in the direction of the fewest molecules of gas to reduce the pressure, producing more of the product with fewer molecules

Question 28

What is the formula equation for the Haber process? - Reversible Reactions

Answer 28

N2 (g) + 3H2 (g) <=> 2NH3 (g)

Question 29

What does the equilibrium do if the temperature of a reaction increases? - Reversible Reactions

Answer 29

The equilibrium shifts to the endothermic side, producing more of the product in an endothermic reaction

Question 30

If the forward reaction in the Haber process (producing ammonia) is exothermic and the temperature increases, what happens? - Reversible Reactions

Answer 30

The equilibrium will shift to the endothermic side (producing Nitrogen and Hydrogen) to reduce the temperature and produce more nitrogen and hydrogen

Question 31

What happens if a concentration of a reactant is increased in a reversible reaction? - Reversible Reactions

Answer 31

The equilibrium will shift to the side with fewer reactants to produce more of the reactants with a smaller concentration

Question 32

What happens when metals react with dilute acids?

Answer 32

Form a Metal salt and hydrogen

Question 33

What do alkalis react with acids to form?

Answer 33

Salt and water