What factors affect the yield of chemical reactions?

Question 1

What are reversible reactions?

Answer 1

most chemical reactions are like: reactants -> products

the reaction is complete - it is an irreversible reaction - it cannot be reversed

although, some reactions are reversible.

a reversible reaction can go forwards or backwards if the reaction conditions are changed

Question 2

What is dynamic equilibrium?

Answer 2

a reversible reaction can reach equilibrium ( a balance) which means the rate of the forward reaction is equal to the rate of the reverse reaction

Question 3

What is a closed system?

Answer 3

where the conditions of the reaction (such as temperature of pressure) are not changed and no substances are added or removed

Question 4

What is in a closed system at equilibrium?

Answer 4

there is no change in the amounts and concentrations of reactants and products

reactants are reacting to form products and products are reacting to re-form reactants at the same rate

this is called dynamic equilibrium

Question 5

How can you change the equilibrium?

Answer 5

by changing the temperature, pressure, concentration of the reactants or products

if the equilibrium is the right of the reaction, the concentration is greater of the products than the concentration of the reactants

if the equilibrium is to the left of the reaction, the concentration of the products is less than the concentration of the reactants

Question 6

What is Le Chatelier’s Principle?

Answer 6

when the conditions of a system are changed, the position of the equilibrium changes to try and restore the original conditions

we can then make predications about - what will happen when certain conditions are changed and what conditions need to be changed to make the highest yield of a substance

Question 7

What is exothermic?

Answer 7

if a reaction is exothermic in the reactant - product direction, le chatelier’s principle shows that increasing the temperature will -

decrease the yield of the products
increase the amount of reactants

Question 8

What is endothermic?

Answer 8

if a reactant is endothermic - then an increase in temperature will -

increase the yield of products
decrease the amount of reactants

Question 9

What do pressure changes only apply to?

Answer 9

reactions involving gases

Question 10

What do pressure changes change?

Answer 10

the equilibrium if there is a difference in the amount of gas in the products and reactants

Question 11

What does an increase and decrease in pressure lead to?

Answer 11

increase in pressure = more product

decrease in pressure = equilibrium will move towards the side of the equation with the greatest number of moles