4.1 RATES OF REACTION

Question 1

What determines if a chemical reaction can happen

Answer 1

If the reactant particles collide with enough energy

Question 2

What is the the activation energy

Answer 2

The minimum amount of energy the reactant particles need to react

Question 3

What happens to particles that collide with little energy

Answer 3

They rebound and remain unchanged

Question 4

What is collision frequency

Answer 4

How often the particles collide with each other

Question 5

What is the percentage succsess

Answer 5

The percentage of the collisions that have enough energy to react

Question 6

What are the 5 factors that affect rate of reaction

Answer 6

1) Solid surface area
2) Temperature
3) Concentration
4) Pressure (gas only)
5) Catalysts

Question 7

Higher surface area increases rate because:

Answer 7

More solid is exposed to other particles - So collision frequency is higher - More successful collisions per unit time

Question 8

Higher concentration / gas pressure increases rate because:

Answer 8

There is a higher proportion of particles per unit volume - So collision frequency is higher - So the proportion of successful collisions is higher per unit time

Question 9

Higher temperature increases rate because:

Answer 9

The particles have more kinetic energy - So the percentage of collisions with enough energy is higher - There are more successful collisions per unit time

Question 10

Catalysts increase rate because:

Answer 10

They provide an alternative route with a lower activation energy - So the percentage of collisions with enough energy is higher - So there are more successful collisions per unit time

Question 11

How do you increase the surface area of a solid

Answer 11

Cutting or grinding it

Question 12

What is the independent variable in the calcium carbonate surface area experiment

Answer 12

the surface area of the calcium carbonate chips

Question 13

What is the dependent variable in the calcium carbonate surface area experiment

Answer 13

Volume of Carbon Dioxide produced

Question 14

Name 3 control variables in the calcium carbonate temperature experiment

Answer 14

Mass of calcium carbonate chips, volume and concentration of HCl, Temperature

Question 15

How does the surface area of the calcium carbonate chips in the surface area experiment affect the results shown on a graph measuring CO2 production

Answer 15

Higher surface area chips have a steeper start because the rate has increased so the volume of carbon dioxide is increasing faster, however they all end in the same place because, the amounts of reactants hasn’t changed, so eventually the reaction produces the same amount of CO2.

Question 16

What is the independent variable in the black cross concentration experiment

Answer 16

The concentration of the sodium thiosulphate

Question 17

What is the dependent variable in the black cross concentration experiment

Answer 17

Time taken for the cross to disappear

Question 18

What is the 3 control variables in the black cross concentration experiment

Answer 18

Total volume of solution, concentration of HCl and temperature

Question 19

How is rate calculated

Answer 19

1 / Time Taken ( in seconds)

Question 20

What is the unit for rate

Answer 20

S ^ -1

Question 21

What are the results of the concentration black cross experiment

Answer 21

Proportional - Straight line through the origin

Question 22

What is the independent variable in the magnesium ribbon temperature experiment

Answer 22

Temperature from Hydrochloric Acid

Question 23

What is the dependent variable in the magnesium ribbon temperature experiment

Answer 23

Time taken for the magnesium ribbon to disappear

Question 24

What are the 4 control variables in the magnesium ribbon temperature experiment

Answer 24

Mass and surface area of magnesium, volume and concentration of HCl

Question 25

What are the results of the magnesium ribbon temperature experiment on a graph

Answer 25

Not a straight line, but as the temperature increases, the rate increases

Question 26

Define a catalyst

Answer 26

Increases the rate of reaction by lowering the activation energy, by providing and alternative pathway

Question 27

Define a catalyst

Answer 27

Increases the rate of reaction by lowering the activation energy, by providing and alternative pathway

Question 28

Why aren't catalysts included in a reaction equation

Answer 28

As they remain unchanged during the reaction

Question 29

What is the balanced symbol equation for the decomposition of Hydrogen Peroxide

Answer 29

2H2O2 --> 2H2O + O2

Question 30

What is the catalysts in the hydrogen peroxide catalyst experiment, and what were there results

Answer 30

Manganese Oxide - Quickest Lead Oxide - Quick Iron Oxide - Slow

Question 31

What elements are usually catalysts

Answer 31

Transition metals

Question 32

How can you measure the effectiveness of different catalysts

Answer 32

Comparing how they affect rate

Question 33

What is the independent variable of the hydrogen peroxide catalyst experiment

Answer 33

Which catalyst is being used

Question 34

What is the dependent variable of the hydrogen peroxide catalyst experiment

Answer 34

Volume of Oxygen produced

Question 35

How can we actively see the oxygen produced

Answer 35

Add a little washing up liquid and it foams it up

Question 36

What are the 3 control variables in the hydrogen peroxide catalyst experiment

Answer 36

Volume and concentration of hydrogen peroxide, temperature, mass and surface area of catalyst

Question 37

A more successful catalyst appears how on a graph compared to others

Answer 37

They have a steeper line but eventually they would all flatten out if you waited long enough

Question 38

What are the 3 catalysts used in the hydrogen peroxide catalyst experiment, and their formulae

Answer 38

Manganese (IV) Oxide - MnO2 Lead (IV) Oxide - PbO2 Iron (III) Oxide - Fe2O3