C3

Question 1

What is the effect of temperature on the rate of reaction? Explain in terms of particles

Answer 1

The rate of reaction increases as the temperature increases.

This is because the particles gain more kinetic energy, meaning they move around faster and therefore collisions will happen more frequently

It also means the particles are more likely to have a successful collision because they have more energy

Question 2

What is the effect of pressure and concentration on rate of reaction (pressure for gases, concentration for liquids/liquid+solid)? Explain in terms of particles

Answer 2

The RoR increases with the pressure/concentration

If there is a higher pressure/concentration, this means there are more particles in the space that the reaction is taking place

This means that the particles are more likely to collide with each other as there is less space for them to move around, therefore more successful collisions will take place

Question 3

When does an explosion take place?

Answer 3

When the reaction is very fast.

Lots of heat and hot gases are released in a short period of time.

These gases expand to create a shock wave that travels at high speed, damaging objects in its path

Question 4

How do catalysts affect a reaction?

Answer 4

They increase the rate of reaction

They do this by lowering the activation energy needed to start the reaction

They also provide a surface for the particles to react on, and therefore they increase the frequency of collisions between particles.

This results in more successful collisions

Question 5

What is the element of which all atomic masses are relative to?

Answer 5

Carbon 12

Question 6

How do you calculate the reacting mass of an element in a reaction given the mass of a different element in the reaction?

Answer 6

(Mass/Mr) = (Mass/Mr)

Which you re-arrange so it’s just one of the masses on its own

Question 7

What is conservation of mass?

Answer 7

The idea that nothing is created or lost in a reaction, only the bonds between elements are broken and re-formed

Question 8

How do you calculate the atom economy of a reaction?

Answer 8

Mr of desired product/total Mr of all products (including that of the desired product)

Question 9

What determines a reaction endothermic ?

Answer 9

The reaction takes in energy from the surroundings to use in the reaction.

If during a reaction the temperature decreases, it is endothermic.

Question 10

That determines a reaction exothermic?

Answer 10

Energy is released during the reaction, transferring TO the surroundings.

If the temperature increases during the reaction, it is exothermic.

Question 11

What type of process is bond making ?

Answer 11

An exothermic process

Question 12

What type of process is bond breaking?

Answer 12

An endothermic process

Question 13

How does one determine whether a reaction is exothermic or endothermic?

Answer 13

Exothermic- the amount of energy taken in to break bonds is LESS than the amount of energy released to make new bonds.

Endothermic- the amount of energy taken in to break bonds is MORE than the amount of energy released to make new bonds.

Question 14

Which is bond making, endothermic or exothermic?

Answer 14

Exothermic

Because the amount of energy taken in to break bonds is LESS than the amount of energy released to MAKE new bonds.

Question 15

Which is bond breaking, endothermic or exothermic?

Answer 15

Endothermic

Because the amount of energy taken in to break bonds is MORE than the amount of energy released to MAKE new bonds.

Question 16

How do you calculate the energy transferred in a chemical reaction?

Answer 16

Energy transferred (J) = mass of liquid heated (g) x specific heat capacity of liquid (J/g) x temp change (degrees C)

Question 17

Advantages of continuous processes

Answer 17

• high production rate
• the process rarely comes to a stop
• small workforce needed
• automated process

Reactants needed are fed continually into a reaction vessel

Question 18

Advantages of batch processes

Answer 18

-low cost

Question 19

Example of a batch process

Answer 19

• Pharmaceuticals

- Other speciality chemicals that are expensive

Question 20

What are the 6 factors that make the development of medicines more expensive?

Answer 20

• research and testing
• labour costs
• energy costs
• raw materials
• time taken for development
• marketing

Question 21

How is a pharmaceutical drug tested for impurities ?

Answer 21

2 ways:

• measuring its melting/boiling point, impurities would alter the MP/BP.
• thin layer chromatography separates coloured substances like ink.

Question 22

What are the main properties of diamond? (6 of them)

Answer 22

• insoluble in water
• doesn’t conduct electricity
• hard
• high melting point
• colourless and transparent
• lustrous (sparkles)

Question 23

Give some uses of diamond

Answer 23

• jewellery (as they are lustrous)
• cutting tools (hard)
• dental drills (hard)

Question 24

Main properties of graphite? (7 of them)

Answer 24

• black
• lustrous
• opaque
• soft
• slippery (weak forces between layers)
• conducts electricity (has free electrons)
• high melting point

Question 25

Give some uses of graphite

Answer 25

• in pencils (the slippery graphite easily wears away on paper)
• lubricants (as the layers of graphite easily slide over each other because there’s no bonds connecting layers)
• as an electrode in electrolysis (as it conducts electricity)

Question 26

What are the potential and current uses of Bucky balls (buckminister fullerene)?

Answer 26

• the Eden project, where lots of plants are grown inside giant buckyballs
• potential use as drug delivery system to a specific area of the body if need be. It could be delivered to the desired area without damaging normal cells

Question 27

Properties of carbon nanotubes? (4 of them)

Answer 27

• very strong
• very stiff
• electrical properties
• large surface area to volume ratio (making it useful as a catalyst)

Question 28

Uses and potential uses of nanotubes?

Answer 28

• used to reinforce graphite in tennis racquets
• used as semiconductors for electrical circuits
• can be used as a catalyst for certain reactions because of their large surface area

Question 29

What is the link between diamond, graphite, buckminister fullerene and nanotubes?

Answer 29

They are all allotropes of carbon, meaning:

• they are all made of carbon
• they are the same state at room temperature
• their carbon atoms are arranged differently, e.g. Each molecule in buckminister fullerene has 60 carbon atoms.