CHAPTER 8

Question 1

what is the rate of reaction

Answer 1

how fast reactants turn into products

Question 2

using a graph, how do you find the rate of reaction at a specific time

Answer 2

draw a tangent to the curve (a straight line)
turns this into a right angled triangle with the tangent as the hypotenuse
calculate the gradient and add the units

Question 3

how can you find the rate of reaction without a graph

Answer 3

how quickly the reactants are used up or how quickly products are made

Question 4

the steeper the gradient of a tangent

Answer 4

the quicker the reaction

Question 5

how to calculate the mean rate of reaction

Answer 5

quantity of reactant used / time

quantity of product formed / time

Question 6

what are the four factors that effect the rate of reaction

Answer 6

concentration, pressure, surface area, temperature, and use of a catalyst

Question 7

what is collision theory

Answer 7

the idea that particles don’t just have to bump each other, they have to do so hard enough to react

Question 8

what is activation energy

Answer 8

the minimum amount of energy particles need before they react

Question 9

why does a smaller surface area speed up a reaction

Answer 9

more area is exposed to the liquid and are able to react

Question 10

a smaller surface area = larger

Answer 10

surface area to volume ratio

Question 11

what are the two reasons why temperature increases rate of reaction

Answer 11

particles collide more often they collide with more energy

Question 12

why does heating a substance mean the particles collide more often

Answer 12

the particles absorb the heat energy and convert it to kinetic

Question 13

why does something fizz when it reacts

Answer 13

release of carbon dioxide

Question 14

how to test for carbon dioxide

Answer 14

turns limewater

Question 15

at room temperature if you increase it by 10 degrees what happened to the rate of reaction

Answer 15

it doubles

Question 16

why are reactions more common with a higher temperature

Answer 16

more particles have a temperature higher than the activation energy

Question 17

why does increasing the concentration increase the rate of reaction

Answer 17

there are more of the particles so collisions are more likely

Question 18

how to test for hydrogen

Answer 18

squeaky pop on a glowing splint

Question 19

how does increasing the pressure increase the rate of reaction

Answer 19

the same number of particles in a smaller space so reactions are more common

Question 20

what is a catalyst

Answer 20

speeds up a reaction without being effected itself

Question 21

how do catalysts work

Answer 21

the provide another route to the products with a lower activation energy so reactants take this route and the reaction is faster

Question 22

advantages of catalysts

Answer 22

cost effective - would be more expensive to pay for extra energy helps environment can be reused

Question 23

what is a reversible reaction

Answer 23

when the reactants react to make the products and the products break down to form reactants

Question 24

what is the symbol for a reversible reaction

Answer 24

two half arrows

Question 25

in a reversible reaction what is endothermic

Answer 25

going from products to reactants

Question 26

in a reversible reaction what is exothermic

Answer 26

reactants to products

Question 27

what is a closed system

Answer 27

when nothing can escape

Question 28

what is equilibrium

Answer 28

when the forward reaction = reverse reaction

Question 29

what is the forward reaction

Answer 29

reactants to products

Question 30

what is the reverse reaction

Answer 30

products to reactants

Question 31

why is equilibrium described as dynamic

Answer 31

because although you cant see it, reactions are still taking place on an atomic level

Question 32

what was la chateliers principle

Answer 32

that when you alter the conditions of an equilibrium, the equilibrium shifts to cancel out the change

Question 33

if you increase one of the reactants in an equilibrium then...

Answer 33

the equilibrium shifts left so the reverse reaction happens faster than the forward and more reactant is made

Question 34

under what pressure conditions will an equilibrium change

Answer 34

when there are different moles of particles on each side

Question 35

if there are the same number of moles on each side of the equilibrium and you increase the pressure, what does it do

Answer 35

nothing

Question 36

if you increase the temperature of one side of the equilibrium what will it do

Answer 36

shift to make more of the endothermic side which results in a drop in temperature

Question 37

decreasing the temperature makes the equilibrium favour the

Answer 37

exothermic reaction

Question 38

how to tell from a graph when a reaction has finished

Answer 38

the line goes flat

Question 39

when is the reaction going fastest from a graph

Answer 39

when the line is steepest

Question 40

what happened when the product of a reaction is a precipitate

Answer 40

the solution goes cloudy

Question 41

how to measure the rate of reaction when the product is a precipitate

Answer 41

draw a cross on paper under the conical flask record the time for it to disappear

Question 42

how to measure rate of reaction using mass of gas given off

Answer 42

the faster the number on the balance drops, the faster rate of reaction measure at frequent intervals

Question 43

how to measure the rate of reaction using volume of gas

Answer 43

use a gas syringe to capture any gas produced more gas produced, faster rate of reaction

Question 44

how to measure the rate of reaction of magnesium and HCl

Answer 44

set up the experiment attach a gas syringe to the top of the conical flask. record the volume of gas produced at regular intervals plot the data and analyse

Question 45

how to measure rate of reaction of sodium thiosulfate and HCl

Answer 45

set up the experiment over a black cross time the time taken for the cross to disappear under the cloudy sulphur

Question 46

how to work out the limiting reactant of the equation

Answer 46

work out the number of moles of each of the reactant look at the equation to see how many moles of one react with the other calculate which will be used up first -the limiting reactant

Question 47

where will dynamic equilibrium only take place

Answer 47

close system

Question 48

what is a dynamic equilibrium

Answer 48

when both reactions are happening but at the same rate, so there is no overall effect

Question 49

what can anhydrous copper sulfate be used to test for

Answer 49

water

Question 50

what are the three changes the equilibrium will try to counteract

Answer 50

temperature concentration pressure

Question 51

what will the equilibrium do if you increase the concentration of the products

Answer 51

shift left to make more reactants