Factors affecting equilibrium - SC15

Question 1

In what conditions can a reversible reaction reach equilibrium?

Answer 1

in a closed system where no substances can leave or enter

Question 2

What happens in a dynamic equilibrium?

(rate of reaction + concentration)

Answer 2

forward and backward reactions still happen at the same rate and concentrations of all reactive substances do not change

Question 3

What is affected in equilibrium from changes of condition?

position of.. and how quickly equilibrium is…

Answer 3

position of dynamic equilibrium and how quickly equilibrium is reached

Question 4

how does temp increase effect the position of equilibrium?

Answer 4

eq moves in the direction of the endothermic reaction

Question 5

how does pressure increase in reactions involving gasses change the position of equilibrium?

Answer 5

eq moves towards the sid eof the balanced equation with fewer molecules of reacting gas

Question 6

how does concentration of reacting substance increase effect the position of equilibrium?

Answer 6

the eq moves away from reacting substance in balanced equation

Question 7

how does a catalyst added effect the position of equilibrium?

Answer 7

no change in position of eq

Question 8

how does temp increase effect the time taken to reach eq

Answer 8

time taken decreases

Question 9

how does pressure increase in reactions involving gases effect the time taken to reach eq

Answer 9

time taken decreases

Question 10

how does concentration of a reacting substance increase effect the time taken to reach eq

Answer 10

time taken decreases

Question 11

how does catalyst added effect the time taken to reach eq

Answer 11

time taken decreases

Question 12

On what basis do chemical manifactureres pick reaction conditions?

they must make a profit

Answer 12

which conditions produce an acceptable product yield in an acceptable time

Question 13

why would a reaction not be allowed to react eq in industrial process?

manifactures must make a profit

Answer 13

if it’s not profitable or takes too long

Question 14

What happens within the harber process reacting nitrogen and hydrogen together to form amonia

(in terms of eq and exo / endothermic reactions)

Answer 14

1. There are fewer molecules of reacting gas on the** right** side - as pressure incraese, the position of eq moves to the right
2. High pressure increases eq yeild of amonia and rate of reaction (pressure never too high because it’s expensive to maintain)
3. Forward reaction is exothermicso backward is endothermic. As temp increases, position of eq moves to the left (direction of endothermic reaction). Low temp increases eq yield but reduces rate of reaction.

• Temp chosen gives acceptable yeild in acceptable time
• Iron catalyst is used due to the fact that it doesn’t change the position of eq and increases rate of reaction

Question 15

What factors need to be taken into account when choosing a reaction pathway?

Answer 15

• availibility/cost of raw materials
• rate of reaction + eq position
• atom economoy, yield + unsefulness of by products

Question 16

What were the steps of obtaining nitric acid via the old method and what was it called? what yeild was obtained?

Answer 16

Birkeland-Eyde process:
1. using a high voltage electric arc made between 2 electrodes to immitate lightining
2. reacting nitrogen + oxygen to form nitrogen monoxide
3. reacting nitrogen monoxide wih oxygen to form N02
4. Dissolve in acid for nitric acid

4% yeild obtained

Question 17

What were the steps of obtaining nitric acid via the current method and what was it called? what yeild was obtained?

Answer 17

Ostwald process:
1. amonia + oxygen <=> nitrogen monoxide + water (forward reaction is exothermic
2. nitrogen monoxide + oxygen <=> nitrogen dioxide (forward reaction is exothermic
3. nitrogen dioxide + oxygen + water -> nitric acid