Reversible reactions and dynamic equilibrium

Question 1

reversible reaction

Answer 1

a chemical reaction that can proceed in either direction, the products can also react to form the reactants

Question 2

describe irreversible reactions

Answer 2

-go to completion (only occur in forward direction)
-products can not easily be changed back into reactants

Question 3

what happens in the reaction of heating hydrated copper (II) sulfate crystals?

Answer 3

hydrated copper (II) sulfate –>
<– anhydrous copper (II) sulfate + water

Question 4

what is water of crystalisation?

Answer 4

-many coloured crystals are hydrated
-when these crystals are heated, the water evaporates leaving an anhydrous salt
-they hydrated salt can be reformed simply by adding water

Question 5

open system

Answer 5

reaction happens in a container where one or more of the reactants or products can escape

Question 6

closed system

Answer 6

reaction happens in a container where neither the reactants or products can escape (due to some kind of lid over the reaction vessel)

Question 7

describe dynamic equilibrium

Answer 7

-rate of the forward reaction = rate of the reverse reaction
-the concentration of reactants and products do not change
-this can only be reached if a reversible reaction is in a closed system

Question 8

what are the factors affecting the position of equilibrium?

Answer 8

-concentration
-pressure
-temperature

Question 9

how does concentration affect the position of equilibrium?

Answer 9

if the concentration of a substance is increased, the equilibrium position moves in the direction away from that substance; if the concentration of a substance is decreased, the equilibrium position moves in the direction towards that substance

Question 10

how does pressure affect the position of equilibrium?

Answer 10

increasing the pressure of a system with gases present, will shift the position of equilibrium to the side with fewer molecules of gas; decreasing the pressure of a system with gases present, will shift the equilibrium to the side with more molecules of gas

Question 11

how does temperature affect the position of equilibrium?

Answer 11

an increase in temperature shifts the equilibrium position in the endothermic direction; a decrease in temperature shifts the equilibrium position in the exothermic direction

Question 12

how does increasing the concentration of the reactants effect the position of equilibrium?

Answer 12

shifts to the right (more products formed)

Question 13

how does decreasing the concentration of the reactants effect the position of equilibrium?

Answer 13

shifts to the left (more reactants formed :( )

Question 14

how does increasing the concentration of the products effect the position of equilibrium?

Answer 14

shifts to the left (more reactants formed :( )

Question 15

how does decreasing the concentration of the products effect the position of equilibrium?

Answer 15

shifts to the right (more products formed)

Question 16

how does increasing pressure change the position of equilibrium?

Answer 16

shifts to side with fewer molecules of gas

Question 17

how does decreasing pressure change the position of equilibrium?

Answer 17

shifts to side with more molecules of gas

Question 18

describe how an increase in temperature effects the position of equilibrium when the forward reaction is exothermic

Answer 18

-shifts to the left (more reactants formed)
-negative energy change

Question 19

describe how an decrease in temperature effects the position of equilibrium when the forward reaction is exothermic

Answer 19

-shifts to the right (more products formed)

Question 20

describe how an increase in temperature effects the position of equilibrium when the forward reaction is endothermic

Answer 20

-shifts to the right (more products formed)
-positive energy change

Question 21

describe how an decrease in temperature effects the position of equilibrium when the forward reaction is endothermic

Answer 21

-shifts to the left (more reactants formed)
-positive energy change