Key Chemsitry Facts To Know

Question 1

What is corrosion

Answer 1

The exposure of metals to oxygen, creating a layer of metal oxide

Question 2

How to work out the number of atoms of an element from its mass and relative atomic mass

Answer 2

• Work out number of moles using n = m/mr
• multiply no of moles by Avogadro’s number (6.02 * 10^23)

Question 3

If a question asks you to design a test for something what two things do you need to describe?

Answer 3

The steps of the experiment and the observations of what should happen

Question 4

When measuring the mass of electrodes what two steps do you need to take?

Answer 4

Rinse and dry the electrodes
Weigh the mass, using a mass balance

Question 4

Why can’t sodium be an electrode

Answer 4

Because it would react with the ions in the solution to form an ionic compound

Question 4

When measuring a titration what do you need to include?

Answer 4

Write the answer to as many possible figures, eg : 23.60 NOT 23.6

Question 5

How can you tell in the copper oxide and sulphuric acid when no more copper oxide needs to be added

Answer 5

The copper oxide stops fizzing, copper sulphate solution stops changing color and there is excess copper oxide as there is lots of black powder left in the bottom

Question 5

What happens if a burrette was rinsed and not dried how will it if at all affect the titre volume

Answer 5

There will be no change

Question 6

Ways to make a titration better

Answer 6

Do a rough titration and measure it to there and then do it drop by drop
Don’t overfill burrette
Wash out the burrette and dry it

Question 7

What color is a lithium ion flame

Answer 7

Red/crimson

Question 8

What color is a sodium ion flame

Answer 8

Yellow

Question 9

What color is a potassium ion flame

Answer 9

Lilac

Question 10

What color is a calcium ion flame

Answer 10

Brick red

Question 11

What color is a copper ion flame

Answer 11

Blue/green

Question 12

What happens to copper as it burns in oxygen?

Answer 12

Turns black slowly as it’s covered in a black layer of copper oxide

Question 13

What happens to magnesium as it burns in oxygen?

Answer 13

Bright white flame burns , white solid is formed

Question 14

What happens to calcium as it burns in oxygen?

Answer 14

Burns with a bright red flame, white solid formed

Question 14

What happens to zinc powder as it burns in oxygen?

Answer 14

A bluefish flame is burned, and a white solid is formed

Question 15

What happens to potassium as it burns in oxygen?

Answer 15

Burns with a lilac flame, white solid is formed

Question 16

What happens to iron filings as it burns in oxygen?

Answer 16

Burns with an orange/yellow flame, a brown solid forms (Fe2O3)

Question 17

Which metals react with acids to form H2

Answer 17

Ca, Mg, Al, Zn and Fe

Question 18

Which metals don’t react with dilute acids

Answer 18

Copper, silver, gold and platinum

Question 19

Which metals react with steam but not water

Answer 19

Aluminum, zinc, and iron

Question 20

Which metals don’t react with water (or steam)

Answer 20

Tin, lead, copper, silver, gold and platinum

Question 21

What happens to copper when it is reacted with HCl

Answer 21

No reaction

Question 22

How do silver, gold and platinum react with oxygen

Answer 22

They don’t!!!

Question 23

How do tin, lead and copper react with O2

Answer 23

Slowly - forming a layer of metal oxide

Question 24

Main use for iron and why

Answer 24

In construction as krs strong and cheap

Question 25

Main use for Aluminium and why

Answer 25

Pilot wires as it is a good conductor of electricity ans a low density

Question 26

What 3 things are copper used for and why

Answer 26

• boilers and hot water pipes as they are unreactive
• electrical wires (ans some saucepans) as they are excellent conductors

Question 27

How is magnesium different from other alkali/alkaline earth metals when it reacts with water/steam?

Answer 27

Magnesium reacts slowly with cold water and fast with steam, whereas the rest all react fast with water

Question 28

3 characteistsics of transition metals

Answer 28

• colourful
• high density
• IS used as a catalyst

Question 29

what to remember on atom economy?

Answer 29

always need to use the balancing numbers eh if it’s 2Pb it needs to be 2*207 so 414

Question 30

3 but 2 main reasons for not 100% percentage yield

Answer 30

• some reactions are incomplete
• may be (unwanted side reactions)
  (LESS IMPORTANT):
• some product is lost in purification/practical losses

Question 31

Graphene structure and conditions

Answer 31

• graphene is a giant covalent structure and each carbon atom is bonded to 3 others
• high melting point
• strong covalent bonds so are strong
• has one free delocalised electron so can conduct electricity

Question 32

fullerene structure and characteristics

Answer 32

• simple molecular
• each carbon atom is joined to 3 others with a free delocalised electron
• only conducts electricity across the surface, so little movement of electrons meaning it’s a bad conductor of electricity
• weak intermolecular forces leading to low melting point and low strength

Question 33

diamond structure

Answer 33

• hard
• each carbon atom is attached to 4 others
• strong covalent bonds means they are hard and have very high melting points
• doesn’t conduct electricity due to no delocalised electrons and so a poor conductor

Question 34

calculate the mass of a hydrogen atom in g, using the data below
Ar of H = 1

Answer 34

1 mole of H is 1g
1g = 6.02 * 10^23 atoms
1/6.02 *10^23 =1.661×10²² g

Question 35

if the glass Pipette isn’t dried after being rinsed in the titration how will it if at all change the titration

Answer 35

it means more dilute sodium hydroxide, meaning less acid is needed to neutralize and hence a decreased value in the titration

Question 36

if the conical flask isn’t dried after being rinsed in the titration how will it if at all change the titratio

Answer 36

no effect, as it does not affect the concentration/ amount of the sodium hydroxide meaning it will not effect the titration