Rates of Reaction (Paper 2)

Question 1

What is meant by rate of reaction

Answer 1

How quickly reactants turn into products

Question 2

Phrase used to describe how quickly reactants turn into products

Answer 2

Rate of reaction

Question 3

2 things to measure when calculating rate of reaction

Answer 3

How quickly the reactant is used up
How quickly the product is produced

Question 4

True or false, some reactions can take years or decades

Answer 4

True (e.g rusting of iron)

Question 5

True or false, some reactions take place in just a fraction of a second

Answer 5

True e.g fireworks

Question 6

Equation to measure how fast the reactants are being used up (rate of reaction)

Answer 6

Quantity of reactants used/ time taken

Question 7

Measuring how quickly the reactant is used up/ how quickly the product Is formed are 2 different ways to tell you the…

Answer 7

Rate of reaction

Question 8

Equation to measure how quickly the product is formed (rate of reaction)

Answer 8

Quantity of product formed/ time taken

Question 9

When measuring rate of reaction, what is the quantity (of reactant/ product) measured in

Answer 9

Grams or cm cubed

Question 10

When measuring rate of reaction, what is time taken measured in

Answer 10

Seconds

Question 11

Do reactions start of fast and slow down or slow and speed up

Answer 11

Start fast but slow down
(That’s why when measuring rate of reaction it’s only an average)

Question 12

When drawing graphs showing rate of reaction, what goes on the x axis

Answer 12

Time (in seconds)

Question 13

When drawing graphs showing rate of reaction what goes on the y axis

Answer 13

Mass of reactant used/ product formed (g or cm cubed)

Question 14

5 factors affecting rate of reaction

Answer 14

Surface area
Temperature
Concentration
(Absence/ presence of) catalyst
Pressure of gases

Question 15

What is meant by collision theory

Answer 15

In order to react, particles must collide with sufficient energy

Question 16

Name for theory where in order to react, particles must collide with sufficient energy

Answer 16

Collision theory

Question 17

The collision theory states that in order to… particles must…with sufficient…

Answer 17

React, collide, energy

Question 18

Name for minimum amount of energy needed for particles to collide with each other and react

Answer 18

Activation energy

Question 19

What is activation energy

Answer 19

Minimum amount of energy needed for particles to collide with each other and react

Question 20

How temperature increases rate of reaction

Answer 20

As temperature increases, particles gain more kinetic energy and move faster so there are more frequent collisions and they will collide with more energy so more of the collisions are successful

Question 21

Both concentration and pressure refer to how many particles there are per unit of…

Answer 21

Volume

Question 22

How increasing pressure/ concentration increases rate of reaction

Answer 22

Increasing pressure/ concentration means that there are more particles per unit of volume so more frequent collisions which increases rate of reaction

Question 23

How increasing surface area increases rate of reaction

Answer 23

The greater the surface area, the more particles there are that are exposed, so more frequent collisions which increases rate of reaction

Question 24

What is a catalyst

Answer 24

Something that speeds up the rate of reaction without being used up

Question 25

Why aren't catalysts used in the reaction equation

Answer 25

They aren't reactants or products

Question 26

What do catalysts do to the activation energy

Answer 26

Lower it (Particles need less energy to collide and react)

Question 27

A catalyst provides an alternative... which lowers the activation energy reaction

Answer 27

Pathway

Question 28

How to calculate rate of reaction at a particular time using graph

Answer 28

Draw tangent at particular time you're interested in and measure gradient

Question 29

When writing an equation what does the double arrow mean

Answer 29

The reaction is reversible

Question 30

How to represent reaction being reversible when writing an equation

Answer 30

Use double arrow (not single one)

Question 31

In a reversible reaction we call the top arrow the... reaction

Answer 31

Forward

Question 32

In a reversible reaction we call the bottom arrow the... reaction

Answer 32

Backward

Question 33

True or false, in a reversible reaction both the forward and backward reaction can happen

Answer 33

True

Question 34

True or false, in a reversible reaction the forward and backward reactions can take place at different rates

Answer 34

True

Question 35

Dynamic equilibrium meaning

Answer 35

Point in reversible reaction where the forward and backward reaction are at the same rate in a closed system (Both reactions are happening but they basically cancel each other out)

Question 36

True or false, in dynamic equilibrium the amount of reactant and product are always equal

Answer 36

False They are always constant but not necessarily the same as each other

Question 37

Equilibrium can only be reached if the reaction is done in what type of system

Answer 37

Closed system

Question 38

True or false, in a closed system no reactants or products can escape

Answer 38

True

Question 39

True or false, at equilibrium the reactants are still turning into products and products still turning back into reactants

Answer 39

True- it's just at the same rate so the amount of reactants and products are constant (not necessarily equal)

Question 40

True or false, equilibrium can only be reached if the reaction is done in a closed system

Answer 40

True Otherwise the reactants/ products could keep escaping

Question 41

True or false, reversible reactions are always exothermic in one direction and endothermic in the other direction

Answer 41

True

Question 42

Hydrated meaning

Answer 42

Water is present

Question 43

Anhydrous meaning

Answer 43

No water is present

Question 44

True or false, the position of equilibrium can change (shift to left/ right) depending on conditions

Answer 44

True

Question 45

Le Chatelier's principle is about the position of what during a reversible reaction

Answer 45

Equilibrium

Question 46

3 main ways to change conditions of closed system

Answer 46

Temperature Pressure Concentration

Question 47

If there are more reactants than products does the equilibrium lie to the left or right

Answer 47

Left

Question 48

If there are more products than reactants does the equilibrium lie to the left or right

Answer 48

Right

Question 49

Why do exothermic reactions have an overall negative energy change

Answer 49

Energy is released to surroundings so lost

Question 50

Why do endothermic reactions have an overall positive energy change

Answer 50

Take in energy from surrounds so energy is gained (added)

Question 51

What is a reversible reaction

Answer 51

Reaction where reactants can turn into products and products can turn back into reactants

Question 52

What is meant by Le Chatelier's principle

Answer 52

If a change is made to a system that's at dynamic equilibrium, the system will try to undo (counteract) the change by favouring either the forward or reverse reaction so that it stays at dynamic equilibrium

Question 53

If the concentration of the product is lowered, which reaction will the system favour and why

Answer 53

Forward reaction Forward reaction turns reactants into products and the way to counteract a decreased product concentration is to increase it

Question 54

If I increase the temperature what will the system do and how

Answer 54

Decrease temperature Favour endothermic reaction which decreases temperature so moves towards endothermic

Question 55

If I decrease the temperature what will the system do and how

Answer 55

Increase temperature by favouring (moving towards) exothermic reaction which increases temperature

Question 56

If I increase concentration what will the system do

Answer 56

Decrease concentration by moving towards reaction that removes that chemical

Question 57

If I decrease concentration what will the system do

Answer 57

Move towards reaction that produces that chemical

Question 58

If I increase pressure what will the system do

Answer 58

Decrease pressure by favouring reaction that produces fewest molecules

Question 59

If I decrease pressure what will the system do

Answer 59

Increase pressure by favouring reaction that produces greatest number of molecules

Question 60

2 units for rate of reaction

Answer 60

g/s Cm cubed/ s (as the quantity of reactant used/ product formed can either be measured in grams or cm cubed and time is always in seconds)

Question 61

5 examples of evidence for a chemical reaction occurring

Answer 61

Change in colour Change in temperature Bubbles/ fizzing Precipitate (solid) formed Odours/ sounds

Question 62

What do particles do if they don't have enough energy to react

Answer 62

Bounce off each other

Question 63

Why does the rate of reaction decrease towards the end

Answer 63

Reactants becoming used up so less frequent collisions

Question 64

How can we tell on a graph where the rate of reaction is highest

Answer 64

Steepest gradient

Question 65

If the temperature of a reversible reaction is raised, what happens to the yield from the exothermic reaction

Answer 65

It decreases