the rate and extent of chemical change 6

Question 1

what is the rate of reaction

Answer 1

how fast the reactants are changed into products

Question 2

how can you find out the speed of reaction

Answer 2

you record the amount of product formed or the the amount of reactant used up

Question 3

how can you tell what reaction is faster on a graph

Answer 3

the steeper the graph the faster but over time the reactants are used up so goes flat

Question 4

How are reaction rates explained

Answer 4

by collision theory (the more collisions there are the faster the reaction but each particle needs enough energy to collide)

Question 5

What does the rate of reaction depend on

Answer 5

Temperature
Surface area
Concentration or pressure
Catalyst

Question 6

what happens to the particles when the temperature increases

Answer 6

particles move faster so collide more frequently

They also have more energy so they can break the bonds

Question 7

what happens to the particles if you increase concentration

Answer 7

more particles in the same amount of water

Question 8

what happens to the particles if you increase pressure

Answer 8

same number of particles occupies a smaller space

Question 9

what happens to the particles if surface area is increased

Answer 9

increase surface area to volume ratio

for the same volume of solid the particles around it will have more area to work on.

Question 10

what happens to the particles if you use a catalyst

Answer 10

speeds up the reaction without being used up

they decrease the activation energy and provide an alternate route.

Question 11

what is a reversible reaction

Answer 11

a reaction that can go both ways

Question 12

How do reversible reactions reach equilibrium

Answer 12

1) as reactants react their concentrations fall so the forward reaction will slow down
2) as more and more products are made and there concentrations increase the backward reaction speeds up
3) when the forward reaction is going at the same rate as the backwards one it has reached equilibrium.`

Question 13

what is equilibrium

Answer 13

concentrations of reactants and products have reached a balance and wont change

Question 14

when can equilibrium be reached

Answer 14

in a closed system where nothing can escape or get in

Question 15

what happens when equilibrium lies to the right

Answer 15

the concentration of products is greater than the reactants

Question 16

what happens when equilibrium lies to the left

Answer 16

the concentration of reactants is greater than the products

Question 17

what is the energy transfer between endothermic and exothermic reactions in a reversible reaction

Answer 17

energy transferred from the surroundings by the endothermic is equal to the energy transferred to the surroundings exothermic

Question 18

name an example of endothermic and exothermic reaction in a reversible reaction

Answer 18

heat blue hydrated copper and this drives off the water leaving white anhydrous copper(endothermic)
if you add water back it goes back to blue(exothermic)

Question 19

what is La Chateliers principle

Answer 19

if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract the change

Question 20

what happens if you decrease the temperature in a reversible reaction

Answer 20

the equilibrium will move in the exothermic direction to produce more heat
this means you will get more products for exothermic and less for endothermic

Question 21

what happens if you increase the temperature in a reversible reaction

Answer 21

the equilibrium will move in the endothermic direction to decrease it
this means you will get more products for endothermic and less for exothermic

Question 22

what happens if you increase the pressure in a reversible reaction

Answer 22

the equilibrium tries to reduce it by moving in the direction where there are fewer molecules of gas

Question 23

what happens if you decrease the pressure in a reversible reaction

Answer 23

the equilibrium tries to increase it by moving in the direction where there are more molecules of gas

Question 24

what happens if you increase the concentration in a reversible reaction

Answer 24

the system tries to decrease it by making more products

Question 25

what happens if you decrease the concentration in a reversible reaction

Answer 25

the system tries to increase it by reducing the amount of reactants