5.1.2 How far?

Question 1

What is homogenous equilibrium?

Answer 1

species ALL have same state

Question 2

What is heterogenous equilibrium?

Answer 2

Species have diff states

Question 3

What nature of species are included in Kc?

Answer 3

Solids and liquids omitted, only includes (g) or (aq)

Question 4

How do you calculate equilibrium quantities/concs when you have the starting mol of reactants, and mol of product at equilibrium?

Answer 4

Use mol of product formed and minus this from the reactants ( use stoichometric ratios) to find mols of everything at equilibrium.

Divide all by volume given to get concentrations

Question 5

Howis a mole fraction calculated?What must it sum to?

Answer 5

mole fraction (A) = mol(A)/ total moles in mixture

1

Question 6

What is partial pressure?

Answer 6

• contribution that gas makes towards the total pressure
• p(A) = mol fraction (A) x total pressure P

Question 7

What does k=1, k=100, and k =0.01 mean?

Answer 7

1: halfway between reactants and products
100: well in favour of products
0.01: well in favour of reactants

Question 8

When does K change and not change?

Answer 8

only changes with temperature!

Question 9

What occurs to K in an EXOTHERMIC reaction as temperature increases?

Answer 9

• decreases
• product yield decreases
• system no longer in equilibrium
• if concs/pp dont change, current ratio now greater than the new k.
• p(products) must decrease
• p(reactants) must increase
• position of equilibrium shifts towards left

Question 10

What occurs to K in an ENDOTHERMIC reaction as temperature increases?

Answer 10

• increases
• product yield increases
• system is no longer in equilibrium so ratio is less than new k if concs dont change
• p(products) must increase
  -p(reactants) must decrease
• position of equilibrium shifts to right

Question 11

How do you approach concentration examples?

Answer 11

• Calculate Kc with initial eq concentrations
• Calculate Kc again with the conc change taken into account
• The ratio must stay the same as before, so the concentrations of products and reactants would change.
• Equilibrium shifts to.. (right if product increases, left is reactant increases)

Question 12

How do you approach pressure examples?

Answer 12

• Doubling of pressure doubles pp of ALL gases. And vise versa.
• Let’s say total pressure was doubled, the ratio would be greater than it should. So then you use that to work out what needs increasing or decreasing. (want to DECREASE that ratio)
• And vise versa

Question 13

How do catalysts affect Kc/Kp?

Answer 13

• affects RATE but not position
• equilibrium is just reached quicker