1. C3 Spaced Learning

2. C3 Measuring Reaction Rate Either measure:
How fast the reactant is used up Or
How fast a product is formed
To find the rate of the reaction from the graph, 1. Find the gradient of the line.
2. Use the axis labels to work out the units. C3
Units of rate depend on what you measured
g/s or g/min
cm3/s or cm3/min
Measuring Reaction Rate
The steeper the line, the faster the reaction.
Horizontal = reaction has stopped.
The limiting reactant is the one that is all used up in the reaction.
If you double the amount of limiting reactant, you double the number of particles available to make the product so, you double the amount of product.

3. Temperature, concentration and pressure
(spot the difference – one answer = many questions!)
When you increase the concentration,
there are more particles in the same volume of liquid,
so the particles collide more often,
and so the reaction is faster.
When you increase the pressure,
there are more particles in the same volume of gas,
so the particles collide more often,
and so the reaction is faster.
Reaction rate depends on
How often the reactant particles collide
How much energy is transferred during the collision (whether is it successful or not.)
When you increase the temperature,
the particles move faster,
so the particles collide more often,
And so the reaction is faster.
When you increase the temperature
The particles have more energy
So a higher proportion of collisions are successful
And so the reaction is faster.
The red line shows the most concentrated, highest pressure or highest temperature reaction.

4. Surface area and catalysts
Possible catalyst
Appearance at the start
Volume of gas produced in 60 seconds. (cm3)
Appearance at the end
None - 45
Copper
Orange/brown 80
Copper sulfate
Blue 98
orange/brown
Magnesium sulfate
White 46
white
Copper is the catalyst because it speeds up the reaction and remains the same at the end.
A catalyst is a substance which speeds up a chemical reaction and is unchanged at the end of the reaction.
Only a small amount of catalyst is needed.
Catalysts are specific to a reaction which means that a catalyst that works for one reaction might not work for another reaction.
Explosions are very fast reactions that produce lots of gas.
Fine combustible powders are dangerous in factories because they can cause an explosion.
The red line is powdered reactant because it is steeper = faster reaction.
When you cut a solid up into smaller pieces,
you increase the surface area,
so the particles collide more often,
and so the reaction is faster.
Surface area and catalysts

5. Reacting Masses Find the relative formula mass of the following.
The relative atomic mass, Ar of C=12, O=16, Mg=24, H=1 and Zn=65
CO = = 44
MgCO = = 84
Mg(OH)2 = 2x(16+1) +24 = 2 x = 58
When you see these in a question, start by doing the adding up the formula sum.
Mass is conserved in a chemical reaction. The particles that are there at the start are there at the end – just rearranged. You cannot make new particles.
CaCO3  CaO + CO2
Show, by calculation, that mass is conserved in this reaction. And calculate the mass of CaO produced if you start with 5g of CaCO3
The relative atomic mass, Ar of Ca = 40, C=12, O=16.
Finding the relative formula masses of the reactants and products:
CaCO3 = = 100
CaO = = 56
CO2 = = 44
So products should = reactants:
100 =
5/100 = ?/56 ? = (5 x 56)/100 ? = 2.8g
Reacting Masses

6. % yield and atom economy
Percentage yield
100% = no product lost
0% = no product made
You must know the formula:
% yield = actual yield x 100
predicted yield
little number ÷ big number x 100
In industry
As high a % yield as possible
Reduces the reactants wasted
Reduces cost
In industry
As high an atom economy as possible
Reduces the production of unwanted products
Makes the process more sustainable
% yield and atom economy
Atom economy
100% = all the atoms in the reactants are in the desired product
High atom economy = greener.
You must know the other formula:
Atom economy = relative formula mass of desired products x 100
sum of the relative formula masses of all products

7. Exothermic = energy given out = temperature increases = bond making
Endothermic = energy taken in = temperature decreases = bond breaking
Energy
In a reaction bonds are broken and made.
If a reaction is exothermic, the energy needed to break the bonds is less than the energy which is given out when the new bonds are made.
To compare the energy transferred per gram of different fuels.
Use a spirit burner
Heat a known mass of water in a copper calorimeter
Measure the mass of fuel burnt
Measure the temperature change
Making it fair and valid
Use the same volume of water,
same temperature change,
same height above the flame,
stir to heat evenly.
The exam paper won’t say this part, but you must remember to use the water mass, not the fuel mass.
Energy transferred (J) = mass of the water x specific heat capacity x change in temperature
You need to be able to rearrange this to find the mass or the change in temperature.
Energy per gram = energy transferred (J) _
mass of fuel burnt (g)

8. Why it is expensive to make, test and develop new pharmaceutical drugs.
Research
Testing – to make sure they are not toxic and will do as they should.
Labour costs
Energy costs
Raw materials
Time taken for development
Marketing
Extracting chemicals from plants:
Crush
Boil to dissolve in a solvent
Chromatography to separate
The purer the chemical, the closer the melting/boiling point will be to the pure substance.
Batch
Continuous
Cost of equipment
Low
High
Rate of production
Shut down and start up times
Short – easy to do
Take a long time, hard to do.
Workforce
Many people – need to be trained.
Few people, no special training
Ease of automation
Difficult
Easy
Type of product
High quality chemicals, seasonal
Chemicals needed in large quantities

9. Diamond, graphite and fullerenes are allotropes of carbon because
they are all made of carbon atoms,
but the atoms are arranged differently
which gives them different properties
Diamond
Jewellery – shiny and attractive
Cutting tools – hard
Does not conduct electricity
All the electrons are involved in C-C bonds
Is hard and has a high melting point
Because the covalent bonds are all strong
So they take lots of energy to break.
Allotropes
Diamond and graphite both have giant molecular structures because all of the atoms are covalently bonded together.
Other giant molecular structures will have similar properties.
Graphite
Pencil leads – slips easily off the pencil, black,
Lubricants – slippery
High melting point – because the covalent bonds are strong and take lots of energy to break.
Slippery – the layers slide over each other easily
Conducts electricity – because only three of the carbons four electrons are involved in covalent bonds so there are free electrons which can move and conduct.
Nanotubes are used in new drug delivery systems because the drug can be placed inside the nanotube cage to stop it damaging other parts of the body while it is delivered to a tumour.
Nanotubes can be used as catalysts as they have a huge surface area for the reactants to collide with.

11. Measuring Reaction Rate
Either measure: Or
To find the rate of the reaction from the graph, 1… 2…
Another way we could measure the reaction rate.
One way we could collect the gas.
Another way we could collect the gas
Units of rate depend on what you measured
Measuring Reaction Rate
How do you know which is fastest?
The limiting reactant is…..
If you double the amount of limiting reactant……….

12. Measuring Reaction Rate
Either measure:
How fast the reactant is used up Or
How fast a product is formed
To find the rate of the reaction from the graph, 1. Find the gradient of the line.
2. Use the axis labels to work out the units.
Units of rate depend on what you measured
g/s or g/min
cm3/s or cm3/min
Measuring Reaction Rate
The steeper the line, the faster the reaction.
Horizontal = reaction has stopped.
The limiting reactant is the one that is all used up in the reaction.
If you double the amount of limiting reactant, you double the number of particles available to make the product so, you double the amount of product.

13. Temperature, concentration and pressure
(spot the difference – one answer = many questions!)
When you increase the concentration,
When you increase the pressure,
Reaction rate depends on
1.. 2.
When you increase the temperature,
When you increase the temperature
The red line shows

14. Temperature, concentration and pressure
(spot the difference – one answer = many questions!)
When you increase the concentration,
there are more particles in the same volume of liquid,
so the particles collide more often,
and so the reaction is faster.
When you increase the pressure,
there are more particles in the same volume of gas,
so the particles collide more often,
and so the reaction is faster.
Reaction rate depends on
How often the reactant particles collide
How much energy is transferred during the collision (whether is it successful or not.)
When you increase the temperature,
the particles move faster,
so the particles collide more often,
And so the reaction is faster.
When you increase the temperature
The particles have more energy
So a higher proportion of collisions are successful
And so the reaction is faster.
The red line shows the most concentrated, highest pressure or highest temperature reaction.

15. Surface area and catalysts
Possible catalyst
Appearance at the start
Volume of gas produced in 60 seconds. (cm3)
Appearance at the end
None - 45
Copper
Orange/brown 80
Copper sulfate
Blue 98
orange/brown
Magnesium sulfate
White 46
white
Explain which substance is the catalyst…
A catalyst is a substance
Only
Catalysts are specific to a reaction which means
Explosions are
Fine powders are dangerous because
The red line is
When you cut a solid up into smaller pieces,
Surface area and catalysts

16. Surface area and catalysts
Possible catalyst
Appearance at the start
Volume of gas produced in 60 seconds. (cm3)
Appearance at the end
None - 45
Copper
Orange/brown 80
Copper sulfate
Blue 98
orange/brown
Magnesium sulfate
White 46
white
Copper is the catalyst because it speeds up the reaction and remains the same at the end.
A catalyst is a substance which speeds up a chemical reaction and is unchanged at the end of the reaction.
Only a small amount of catalyst is needed.
Catalysts are specific to a reaction which means that a catalyst that works for one reaction might not work for another reaction.
Explosions are very fast reactions that produce lots of gas.
Fine combustible powders are dangerous in factories because they can cause an explosion.
The red line is powdered reactant because it is steeper = faster reaction.
When you cut a solid up into smaller pieces,
you increase the surface area,
so the particles collide more often,
and so the reaction is faster.
Surface area and catalysts

17. Reacting Masses Find the relative formula mass of the following.
The relative atomic mass, Ar of C=12, O=16, Mg=24, H=1 and Zn=65
CO2
MgCO3
Mg(OH)2
When you see these in a question, start by doing the adding up the formula sum.
Mass is conserved in a chemical reaction because
CaCO3  CaO + CO2
Show, by calculation, that mass is conserved in this reaction. And calculate the mass of CaO produced if you start with 5g of CaCO3
The relative atomic mass, Ar of Ca = 40, C=12, O=16.
Reacting Masses

18. Reacting Masses Find the relative formula mass of the following.
The relative atomic mass, Ar of C=12, O=16, Mg=24, H=1 and Zn=65
CO = = 44
MgCO = = 84
Mg(OH)2 = 2x(16+1) +24 = 2 x = 58
When you see these in a question, start by doing the adding up the formula sum.
Mass is conserved in a chemical reaction. The particles that are there at the start are there at the end – just rearranged. You cannot make new particles.
CaCO3  CaO + CO2
Show, by calculation, that mass is conserved in this reaction. And calculate the mass of CaO produced if you start with 5g of CaCO3
The relative atomic mass, Ar of Ca = 40, C=12, O=16.
Finding the relative formula masses of the reactants and products:
CaCO3 = = 100
CaO = = 56
CO2 = = 44
So products should = reactants:
100 =
5/100 = ?/56 ? = (5 x 56)/100 ? = 2.8g
Reacting Masses

19. % yield and atom economy
Percentage yield
You must know the formula:
In industry
As high a % yield as possible because
In industry
As high an atom economy as possible
% yield and atom economy
Atom economy
100% =
High =
You must know the other formula:

20. % yield and atom economy
Percentage yield
100% = no product lost
0% = no product made
You must know the formula:
% yield = actual yield x 100
predicted yield
little number ÷ big number x 100
In industry
As high a % yield as possible
Reduces the reactants wasted
Reduces cost
In industry
As high an atom economy as possible
Reduces the production of unwanted products
Makes the process more sustainable
% yield and atom economy
Atom economy
100% = all the atoms in the reactants are in the desired product
High atom economy = greener.
You must know the other formula:
Atom economy = relative formula mass of desired products x 100
sum of the relative formula masses of all products

21. Energy Exothermic = Endothermic =
Explain why a reaction is exothermic overall.
To compare the energy transferred per gram of different fuels.
Making it fair and valid
The exam paper won’t say this part, but you must remember to use the water mass, not the fuel mass.
Energy transferred (J) = mass of the water x specific heat capacity x change in temperature
You need to be able to rearrange this to find the mass or the change in temperature.
Energy per gram = energy transferred (J) _
mass of fuel burnt (g)

22. Exothermic = energy given out = temperature increases = bond making
Endothermic = energy taken in = temperature decreases = bond breaking
Energy
In a reaction bonds are broken and made.
If a reaction is exothermic, the energy needed to break the bonds is less than the energy which is given out when the new bonds are made.
To compare the energy transferred per gram of different fuels.
Use a spirit burner
Heat a known mass of water in a copper calorimeter
Measure the mass of fuel burnt
Measure the temperature change
Making it fair and valid
Use the same volume of water,
same temperature change,
same height above the flame,
stir to heat evenly.
The exam paper won’t say this part, but you must remember to use the water mass, not the fuel mass.
Energy transferred (J) = mass of the water x specific heat capacity x change in temperature
You need to be able to rearrange this to find the mass or the change in temperature.
Energy per gram = energy transferred (J) _
mass of fuel burnt (g)

23. Why it is expensive to make, test and develop new pharmaceutical drugs.
Extracting chemicals from plants: 1. 2. 3
The purer the chemical, …
Batch
Continuous
Cost of equipment
Rate of production
Shut down and start up times
Workforce
Ease of automation
Type of product

24. Why it is expensive to make, test and develop new pharmaceutical drugs.
Research
Testing – to make sure they are not toxic and will do as they should.
Labour costs
Energy costs
Raw materials
Time taken for development
Marketing
Extracting chemicals from plants:
Crush
Boil to dissolve in a solvent
Chromatography to separate
The purer the chemical, the closer the melting/boiling point will be to the pure substance.
Batch
Continuous
Cost of equipment
Low
High
Rate of production
Shut down and start up times
Short – easy to do
Take a long time, hard to do.
Workforce
Many people – need to be trained.
Few people, no special training
Ease of automation
Difficult
Easy
Type of product
High quality chemicals, seasonal
Chemicals needed in large quantities

25. Diamond, graphite and fullerenes are allotropes of carbon because1. 2. 3.
Diamond
Jewellery –
utting tools
Does not conduct electricity
Because
Is hard and has a high melting point
because
Allotropes
Diamond and graphite both have giant molecular structures because
Graphite
Pencil leads –
Lubricants –
High melting point – because
Slippery –
Conducts electricity –
Nanotubes are used in new drug delivery systems because
Nanotubes can be used as catalysts as

26. Diamond, graphite and fullerenes are allotropes of carbon because
they are all made of carbon atoms,
but the atoms are arranged differently
which gives them different properties
Diamond
Jewellery – shiny and attractive
Cutting tools – hard
Does not conduct electricity
All the electrons are involved in C-C bonds
Is hard and has a high melting point
Because the covalent bonds are all strong
So they take lots of energy to break.
Allotropes
Diamond and graphite both have giant molecular structures because all of the atoms are covalently bonded together.
Other giant molecular structures will have similar properties.
Graphite
Pencil leads – slips easily off the pencil, black,
Lubricants – slippery
High melting point – because the covalent bonds are strong and take lots of energy to break.
Slippery – the layers slide over each other easily
Conducts electricity – because only three of the carbons four electrons are involved in covalent bonds so there are free electrons which can move and conduct.
Nanotubes are used in new drug delivery systems because the drug can be placed inside the nanotube cage to stop it damaging other parts of the body while it is delivered to a tumour.
Nanotubes can be used as catalysts as they have a huge surface area for the reactants to collide with.