chemistry specification part 8

Question 1

Evaluate the advantages of recycling metals, including valuable raw materials.

Answer 1

-extracting raw materials takes lots of energy and they’re running out so it’s important to conserve them.
-saves energy as this process uses a small fraction of the energy needed to extract material from scratch

Question 2

what is a life cycle assessment?

Answer 2

looks at each stage of the product’s life and works out the potential environmental impact of each stage like the manufacture,product use and diposal

Question 3

what is dynamic equilibria?

Answer 3

the forwards and backward reactions are both happening at the same time and at the same rate and the concentration of the products has reached a balance and won’t change.

Question 4

Recall the conditions for the Haber process.

Answer 4

-temperature 450 °C
-pressure 200 atmospheres
- iron catalyst

Question 5

how can equilibrium be reached?

Answer 5

if the reversible reaction is in a closed system so none of the products or reactants escapes.

Question 6

what three things can change the position of equilibrium (which changes the amounts of products and reactants present at equilibrium)?

Answer 6

temperature, pressure (equilibria involving gases) and concentration (for reactants and products)

Question 7

what is a reversible reaction?

Answer 7

where the products can react with each other to produce the original reactants

Question 8

describe what happens if you change the temperature in a equilibria

Answer 8

if you decrease the temperature, the equilibrium will move in the exothermic direction to produce more heat. If you increase the temperature, the equilibrium will move in the endothermic direction to absorb extra heat.

Question 9

describe what happens if you change the pressure in equilibria

Answer 9

if you increase the pressure, the equilibria will move to the side that has fewer moles of gas to reduce pressure. If you decrease the pressure, the equilibria will move towards the side that has more moles of gas to increase pressure.

Question 10

describe hat happens when you change the concentration in equilibria

Answer 10

if you increase the concentration of the reactants, the equilibrium will move to the right to use up the reactants making more products).

If you increase the concentration of the products, the equilibrium will move to the left to use up the products (making more reactants).

decreasing the concentration will have the
opposite effect.