How much?

Question 1

Concerning emperical formula, what does MADR stand for?

Answer 1

Mass
Relative atomic mass
Divide
Ratio

Question 2

How do we found out the relative formula mass of a compound?

Answer 2

Add the relative formulas together

Question 3

What is the formula for working out the % of element in a compound?

Answer 3

mass of element / total mass of compound x 100

Question 4

How do we work out percentage yield?

Answer 4

product made / product possible x 100

Question 5

What is a food additive?

Answer 5

A substance added to the food to improve its shelf life, taste or appearance

Question 6

What technique is used to identify food additives?

Answer 6

Chromatography

Question 7

What technique is used to separate compounds?

Answer 7

Gas chromatography

Question 8

After the compounds are separated where are they taken to?

Answer 8

The mass spectrometer

Question 9

In which part of the apparatus is the relative molecular mass of the compound measured?

Answer 9

Computer

Question 10

What is a reversible reaction?

Answer 10

A reaction where products can react to make the reactants

Question 11

How does a reversible reaction differ from a normal reaction?

Answer 11

Reversible reactions are able to make reactants out of products and products out of reactants

Question 12

What is the relative mass of a proton, neutron and electron?

Answer 12

Proton -1
Neutron -1
Electron - Very small

Question 13

What is the total number of protons and neutrons in an atom called?

Answer 13

The mass number

Question 14

What are isotopes?

Answer 14

Atoms with different numbers of neutrons

Question 15

What compares the mass of atoms of the element

with the 12C isotope?

Answer 15

The relative atomic mass of an element

Question 16

What is the relative formula mass of a compound?

Answer 16

the relative atomic masses of the

atoms added together

Question 17

The relative formula mass of a substance, in grams,

is known as…

Answer 17

One mole of that substance

Question 18

Give 3 advantages of instrumental methods when analysing substances.

Answer 18

Accurate
Sensitive
Rapid
Useful when the sample is small

Question 19

What do we use to identify additives in food?

Answer 19

Chemical analysis (paper chromatography)

Question 20

What does gas chromatography allow?

Answer 20

The separation of a mixture in compounds

Question 21

What can we do with the time taken for a substance to travel through the column?

Answer 21

Identify the substance

Question 22

What does the mass spectrometer do?

Answer 22

1. gives the relative molecular mass of each of the
   separated substances
2. Identifies substances leaving at the end of the column

Question 23

What gives the molecular mass?

Answer 23

The molecular ion peak

Question 24

Why is it not always possible to

get the calculated amount of a product? (3 marks)

Answer 24

1. The reaction may not get completed because it’s reversible
2. Some of the product gets lost
3. The expected reaction may not happen and the reactants may react differently

Question 25

What is the amount of product obtained called?

Answer 25

Yield

Question 26

How do you calculate the rate of a reaction?

Answer 26

The amount of reactant used/Product formed ------------------------------------------------------------------ time

Question 27

What is activation energy?

Answer 27

The minimum amount of energy particles need to react

Question 28

Explain the collision theory

Answer 28

Chemical reactions can only happen when reacting | particles collide with each other and have enough energy

Question 29

How does increasing temperature help the rate of reaction?

Answer 29

Particles gain energy when heated and move faster and collide more often

Question 30

How does increasing pressure help the rate of reaction?

Answer 30

Increases the frequency of collisions

Question 31

How does increasing concentration help the rate of reaction?

Answer 31

Increases the frequency of collisions

Question 32

How does increasing surface area help the rate of reaction?

Answer 32

Increases the frequency of collisions

Question 33

What do catalysts do?

Answer 33

Speed up the rate of chemical reactions

Question 34

In a chemical reaction does the catalyst get used up?

Answer 34

No

Question 35

Why are catalysts important in industry?

Answer 35

Speeds up the reaction and reduces cost

Question 36

When chemical reactions happen what is transferred to or from the surroundings?

Answer 36

Energy

Question 37

What kind of reaction transfers energy to the surroundings?

Answer 37

Exothermic

Question 38

What kind of reaction takes in energy from the surroundings?

Answer 38

Endothermic

Question 39

if a reversible reaction is exothermic in one direction, what is it in the other direction?

Answer 39

Endothermic