C8 - Rates and Equilibrium

Question 1

What is the rate?

Answer 1

Tells us how fast reactants turn into products.

Question 2

What are the two equations for mean rate of reaction?

Answer 2

quantity of product formed/ time

quantity of reactant used up/ time

Question 3

What is rate measured in?

Answer 3

g or cm^3/s

Question 4

What are the 3 ways to measure rate?

Answer 4

• measuring the decreasing mass of a reaction.

-measuring the decreasing light passing through a solution.

-measuring the increasing volume of gas being given off.
a) using a glass syringe
b) using a measuring cylinder and trough.

Question 6

For reactions to take place reactants must collide with?

Answer 6

Correct orientation and enough energy

Question 7

Rate of reaction ____ if the frequency of successful collision ____.

Answer 7

Increase

Question 8

What are the 5 factors that affect the rate of reaction by increasing frequency of successful collision?

Answer 8

Temperature
Surface area
Use of catalyst
Concentration of solutions
Pressure of gases

Question 9

Why does rate of reaction increase when temperature increases?

Answer 9

Because particles have more energy and more around faster therefore particles collide more often and with more energy which increases the frequency of successful collisions.

Question 10

Why does rate of reaction increase when concentration increases?

Answer 10

Because there’s more particles in a volume and therefore particles are closer together which increases the frequency of successful collisions.

Question 11

Why does rate of reaction increase when a catalyst is introduced?

Answer 11

Because catalysts prouve an alternative route for the reaction with a lower activation energy which increases the frequency of successful collisions.

Question 12

Why does rate of reaction increase when surface area of particles increases?

Answer 12

Because increase surface area means more particles are exposed therefore in contact with each other which increases the frequency of successful collisions.

Question 13

Give examples of controlled reactions.

Answer 13

Nuclear to avoid explosions.
Rusting to reduce reactions by catalysts.
Mixing stuff to reduce time by giving more energy.
Combustion.
Food going bad by adding preservatives and reduce temp.

Question 14

What is a catalyst?

Answer 14

A substance which increases the rate of reaction without being used up in the reaction.

Question 15

Catalysts provide an alternative reaction route with a _____ activation energy.

Answer 15

Lower

Question 16

What are examples of reversible reactions?

Answer 16

Melting and freezing
Neutralisation

Question 17

What’s a word equation example of a reversible reaction?

Answer 17

Hydrated copper sulphate —-> anhydrous copper sulphate + water

Question 18

What’s dynamic equilibrium?

Answer 18

When the reactants are turning into products at the same rate as the products are turning back into reactants.

Question 19

What are the three affecting compositions of dynamic equilibrium?

Answer 19

Concentration, temperature and pressure

Question 20

Who is le chatelier?

Answer 20

A french chemist who observed equilibrium mixtures.

Question 21

What does yield mean?

Answer 21

Amount

Question 22

How does concentration alter conditions?

Answer 22

Increasing the concentration of the reactant will ‘push’ or move the equilibrium to the product side as it opposes this increase and vice versa.

Question 23

How does altering temperature affect conditions?

Answer 23

Increasing the temperature of the system will move the equilibrium in the endothermic reaction.

Question 24

How does altering pressure change conditions?

Answer 24

Increasing the pressure of a system moves the equilibrium to the side with the fewer moles of gas and vice versa.