Chemistry Paper 1 Revision

Question 1

What is an element?

Answer 1

A substance containing only one type of atom

Question 2

What is a compound?

Answer 2

A substance containing two or more types of atoms chemically bonded

Question 3

What is a mixture?

Answer 3

Different substances not chemically bonded together. e.g. water

Question 4

What is filtration?

Answer 4

Filtration removes insoluble particles from a liquid. e.g. sand and water

Question 5

What is evaporation?

Answer 5

Evaporation leave behind crystals of a dissolved substance if heated gently.

Question 6

What is distillation?

Answer 6

Distillation involves condensing the evaporated solvent from evaporation and collects it.

Question 7

What is chromatography?

Answer 7

Chromatography causes substances to rise up chromatography paper by capillary action where lighter particles move further up.

Question 8

How do you change the state of matter?

Answer 8

To melt of evaporate a substance you need to overcome the electrostatic forces of attraction between particles by energy (heat)

Question 9

Describe the development of the atom.

Answer 9

• John Dalton: Popularised the theory that matter is made of invisible particles.
• JJ Thomson: Created the plum pudding model.
• Ernest Rutherford: Discovered the nucleus was small and positively charged.
• Neils Bohr: Deduced that electrons exist in ‘shells’. James Chadwick determined that the nucleus must contain neutrons.

Question 10

What makes an ion?

Answer 10

An atom must have the same number of electrons as protons in order to be neutral. If not, it is an ion.

Question 11

What is the mass number?

Answer 11

The mass number is the number of protons + no. of neutrons in a nucleus

Question 12

What is an isotope?

Answer 12

Same element but has a different number of neutrons

Question 13

How do you find the number of neutrons?

Answer 13

Top - Bottom = neutrons

Question 14

How were elements ordered in the first periodic tables?

Answer 14

• Dimitri Mendeleev: Ordered elements by their atomic ‘weight’ with gaps for predicted undiscovered elements.

Question 15

What does the group in the PT show?

Answer 15

How many electrons are in the outer shell

Question 16

What does a period show you in the PT?

Answer 16

How many shells an element has

Question 17

Describe Group 1.

Answer 17

Alkalis, More reactive down the group because electrons are further away from nucleus.

Question 18

Describe Group 7.

Answer 18

Halogens, Less reactive going down the group because electrons are further away from nucleus = less easily accepted

Question 19

Describe group 0.

Answer 19

Noble gases, Inert = full outer shell

Question 20

What is metallic bonding?

Answer 20

The bonding of metal and a metal
They form a lattice of ions surrounded by a sea of delocalised electrons.
Because the electrons can move metals make good conductors

Question 21

What is Ionic Bonding?

Answer 21

Bonding between metal and non metal
The metal donates electron and the non metal gains electrons both to gain a full outer shell.

Question 22

Describe Ionic structures.

Answer 22

Ions are arranged in a lattice of repeating unites of positive and negative ions- these form a crystal.
Ionic substances have high melting/boiling points due to strong ionic bonds.
They can conduct electricity only in liquid.

Question 23

What is covalent bonding?

Answer 23

The bond between a non metal and a non metal.
Atoms SHARE electrons to gain a full
outer shell.
CANNOT conduct electricity

Question 24

Explain giant covalent bonds.

Answer 24

Examples:
- Diamond - Hard substance and very high melting point.
- Graphite - Delocalised electrons form weak bonds between layers, can conduct electricity and layers can slide past eachother due to weak bonds.

Question 25

What is a graphene?

Answer 25

A single-atom-thick layer of carbon atoms arranged in a hexagonal lattice.

Question 26

What is a fullerene?

Answer 26

A molecular allotrope of carbon that forms hollow structures, like spheres or tubes, made up of carbon atoms

Question 27

What is an allotrope?

Answer 27

Each of two or more different physical forms in which an element can exist. Graphite, charcoal, and diamond are all allotropes of carbon.

Question 28

What is the formula for moles?

Answer 28

'Grams'/'RAMS'

Question 29

What is 1 mole of a substance?

Answer 29

When the mass of a substance in grams is the same as the atomic number of the element

Question 30

What is the formula of % yield?

Answer 30

total mass of products/total mass of reactants x 100

Question 31

What is atom economy?

Answer 31

Atom Economy tells you how much of a desired product can be made in a reaction compared to the total mass of reactants.

Question 32

What is the formula for atom economy?

Answer 32

RAMS of desired product/total RAM of reactants x 100

Question 33

What is % Yield?

Answer 33

% Yield tells you what mass a product is made in a reaction in reality, compared to the maximum theoretical mass that could be made.

Question 34

What does one mole of gas take up?

Answer 34

A volume of 24dm^3

Question 35

How do you calculate moles of gas from volume?

Answer 35

divide the volume by 24

Question 36

What is a dm^3?

Answer 36

1000 cm^3

Question 37

What is an acid + alkali?

Answer 37

Salt + Water

Question 38

What is a change of 1 pH?

Answer 38

A x10 change in concentration of H or OH ions

Question 39

What is titration?

Answer 39

We use a biurette to measure what volume of acid/alkali is needed to neutralise, to allow us to calculate an unknown concentration

Question 40

What is the method of titration?

Answer 40

1) Measure 50ml of alkali of known concentration using a glass pipette, put in a conical flask with methyl orange indicator 2) Put acid in biurette up to 0ml mark, open tap and let it drip into flask 3) Once it goes pink, stop swirling. If it stays, neutralisation occurred. 5) Use moles to calculate unknown concentration.