C2a

Question 1

What is the atomic number?

Answer 1

The number of protons / electrons

Bottom number

Question 2

What is the mass number?

Answer 2

Top number

No of protons and neutrons

Question 3

Mass of protons, neutrons and electron

Answer 3

P- 1
N-1
E- 1/2000

Question 4

What is a compound?

Answer 4

Formed when atoms of two or more elements are chemically combined together.

Question 5

What is an isotope?

Answer 5

Different atomic forms of the same element, which have the same number of protons but different number of neutrons.

Question 6

What is ionic bonding?

Answer 6

atoms loose or gain electrons to form ions (charged particles)

Question 7

How does ionic bonding work?

Answer 7

If an atom has 1 electron in its outer shell or only needs 1 to be complete ionic bonding is conducted as they want to be the same as a nobel gas. The two atoms latch onto each other and gain/loose electrons.

Question 8

Properties of an ionic compound?

Answer 8

Always have giant ionic lattices
Closely packed regular lattice arrangement
Strong electrostatic forces of attraction
High melting and boiling points as lots of energy is needed to break the electrostatic forces.
dissolve easily as ions can separate to carry electric current

Question 9

If an element gains/looses an electron what charge to they get?

Answer 9

Gain - negative

Loose - positive

Question 10

What is an ion

Answer 10

Atoms that have lost or gained an electron

Question 11

What happens is a negative and positive ion react with each other?

Answer 11

The two balance each other out.

eg Na+ and Cl- become NaCl

Question 12

How do you draw diagrams of two atoms that are ions or have been ionically bonded?

Answer 12

You have to move the electron in the outer shell and then put brackets around each atom with the charge in the corner
_              _
|                  |  + or -
|                  |
|                  |
|_              _|

Question 13

What is covalent bonding?

Answer 13

When atoms share electrons in their outer shell to get full outer shells and be like nobel gases

Question 14

How is methane covalently bonded?

Answer 14

1 carbon and 4 hydrogen

Question 15

How is ammonia covalently bonded?

Answer 15

1 nitrogen and 3 hydrogen

Question 16

Properties of a simple molecular substance

Answer 16

Strong covalent bonds to form small molecules
Weak intermolecular forces
Low melting and boiling point
Dont conduct electricity as they are ions so no electric charge
Gases and liquid at room temp
E.g oxygen, water, chlorine

Question 17

Properties of giant covalent structures

Answer 17

No charged ions
Strong covalent bonds
High boiling and melting points
Dont conduct electricity
e.g Diamond, graphite and silica

Question 18

Properties of a diamond

Answer 18

rigid
each carbon had 4 covalent bonds
shape of a pyramid 
No charged ions
Strong covalent bonds
High boiling and melting points
Dont conduct electricity

Question 19

Properties of graphite

Answer 19

each carbon has 3 covalent bonds
in layers so can slide over each other
soft and slippery
No charged ions
Strong covalent bonds
High boiling and melting points
weak intermolecular forces

Question 20

Properties of metals

Answer 20

Giant structure
strong forces of electrostatic attraction
Bent and shaped easy
Conduct electricity/heat

Question 21

Why can a metal conduct electrify

Answer 21

Have free electrons

The delocalised electrons come from outer shell and are free to move which carries heat and electricity through metal

Question 22

Why can metals be bent and shaped easily?

Answer 22

There atoms are in layers meaning that they can slide over each other easily

Question 23

What is an alloy?

Answer 23

Mix of two or more metals

Question 24

Why are alloys harder than pure metals?

Answer 24

They have different sized atoms which distort the atoms layers so they can’t slide over each other easily making them harder.

Question 25

Example of a smart material

Answer 25

Shape memory alloy alloy made from nickel and titanium You can bend and twist it but it will always return to its original shape. Used in glasses and braces

Question 26

What is a nanoparticle?

Answer 26

A very small particle which is around 1-100 nanometers across.

Question 27

What is nano science?

Answer 27

The science of very small particles and develop new uses for them

Question 28

Properties and uses of nanoparticles?

Answer 28

Very strong huge surface area compared to volume - so used as catalysts Used in cosmetics like suncreams so they don't leave white on skin Conduct electricity - so used for small electric circuits.

Question 29

What is the difference between thermosetting and thermosoftening polymers

Answer 29

Thermosoftening - don't have cross-linking chains so they are easy to melt. They can be remoulded as many times as you like. Weak intermolecular forces Thermosetting - Strong intermolecular forces between crosslinks that hold chains firmly together so are very solid structures that are strong, hard and rigid.

Question 30

How is low density polythene made?

Answer 30

Heating ethene at about 200 degrees under high pressure - is flexible and used for bags and bottles

Question 31

How is high density polythene made?

Answer 31

heating ethene - Lower temperature and pressure with a catalyst. - more rigid and used in water tanks and drainpipes.

Question 32

What is relative atomic mass?

Answer 32

Ar The mass number of an element Basically how heavy it is compared to carbon-12

Question 33

What is relative formula mass?

Answer 33

Mr | The relative atomic mass of each individual component of the compound, added together.

Question 34

What is a mole?

Answer 34

The relative formula mass (Ar / Mr) of a substance in grams is known as one mole of that substance

Question 35

How do you work out the number of moles?

Answer 35

Number of moles = Mass in g (of element/compound ----------------------------------------- Mr (of element/compound)

Question 36

How do you calculate percentage mass of an element in a compound?

Answer 36

Ar x No of atoms (of that element) -------------------------------------------------- x 100 Mr (of whole compound)

Question 37

How do you find the empirical formula?

Answer 37

1. List all the elements in the compound 2. Underneath write how much is being used of that element in the experiment 3. Divide this number by the Ar of that element 4. Turn the numbers into nice whole numbers by timing by 10 5, Divide the 2 numbers so they are in the simplest form

Question 38

How do you calculate mass in a reaction?

Answer 38

1. Write out the balanced equation 2. Work out the Mr for the things involved in question 3. Then divide the 2 numbers to find 1g of the substance 4. Times that number by the number asked for in the question.

Question 39

How do you work out percentage yield?

Answer 39

``` Actual yield (grams) ------------------------------ x 100 Predicted yield (grams) ```

Question 40

Why do you never get 100% yield?

Answer 40

Reaction is reversible Lost throughout the experiment Sometimes unexpected reaction take place that use reactants.

Question 41

How can you separate artificial colours?

Answer 41

Paper chromatography | When you put ink/dye on filer paper then put into into a solvent (water) This will force colours to separate.

Question 42

How does gas chromatography work?

Answer 42

A gas is carried through a column that is packed with a solid material. The substances travel through at different speeds causing them to sepertate.