Key Chemsitry Facts To Know Flashcards
What is corrosion
The exposure of metals to oxygen, creating a layer of metal oxide
How to work out the number of atoms of an element from its mass and relative atomic mass
- Work out number of moles using n = m/mr
- multiply no of moles by Avogadro’s number (6.02 * 10^23)
If a question asks you to design a test for something what two things do you need to describe?
The steps of the experiment and the observations of what should happen
When measuring the mass of electrodes what two steps do you need to take?
Rinse and dry the electrodes
Weigh the mass, using a mass balance
Why can’t sodium be an electrode
Because it would react with the ions in the solution to form an ionic compound
When measuring a titration what do you need to include?
Write the answer to as many possible figures, eg : 23.60 NOT 23.6
How can you tell in the copper oxide and sulphuric acid when no more copper oxide needs to be added
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
What happens if a burrette was rinsed and not dried how will it if at all affect the titre volume
There will be no change
Ways to make a titration better
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
What color is a lithium ion flame
Red/crimson
What color is a sodium ion flame
Yellow
What color is a potassium ion flame
Lilac
What color is a calcium ion flame
Brick red
What color is a copper ion flame
Blue/green
What happens to copper as it burns in oxygen?
Turns black slowly as it’s covered in a black layer of copper oxide
What happens to magnesium as it burns in oxygen?
Bright white flame burns , white solid is formed
What happens to calcium as it burns in oxygen?
Burns with a bright red flame, white solid formed
What happens to zinc powder as it burns in oxygen?
A bluefish flame is burned, and a white solid is formed
What happens to potassium as it burns in oxygen?
Burns with a lilac flame, white solid is formed
What happens to iron filings as it burns in oxygen?
Burns with an orange/yellow flame, a brown solid forms (Fe2O3)
Which metals react with acids to form H2
Ca, Mg, Al, Zn and Fe
Which metals don’t react with dilute acids
Copper, silver, gold and platinum
Which metals react with steam but not water
Aluminum, zinc, and iron
Which metals don’t react with water (or steam)
Tin, lead, copper, silver, gold and platinum
What happens to copper when it is reacted with HCl
No reaction
How do silver, gold and platinum react with oxygen
They don’t!!!
How do tin, lead and copper react with O2
Slowly - forming a layer of metal oxide
Main use for iron and why
In construction as krs strong and cheap
Main use for Aluminium and why
Pilot wires as it is a good conductor of electricity ans a low density
What 3 things are copper used for and why
- boilers and hot water pipes as they are unreactive
- electrical wires (ans some saucepans) as they are excellent conductors
How is magnesium different from other alkali/alkaline earth metals when it reacts with water/steam?
Magnesium reacts slowly with cold water and fast with steam, whereas the rest all react fast with water
3 characteistsics of transition metals
- colourful
- high density
- IS used as a catalyst
what to remember on atom economy?
always need to use the balancing numbers eh if it’s 2Pb it needs to be 2*207 so 414
3 but 2 main reasons for not 100% percentage yield
- some reactions are incomplete
- may be (unwanted side reactions)
(LESS IMPORTANT): - some product is lost in purification/practical losses
Graphene structure and conditions
- 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
fullerene structure and characteristics
- 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
diamond structure
- 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
calculate the mass of a hydrogen atom in g, using the data below
Ar of H = 1
1 mole of H is 1g
1g = 6.02 * 10^23 atoms
1/6.02 *10^23 =1.661×10²² g
if the glass Pipette isn’t dried after being rinsed in the titration how will it if at all change the titration
it means more dilute sodium hydroxide, meaning less acid is needed to neutralize and hence a decreased value in the titration
if the conical flask isn’t dried after being rinsed in the titration how will it if at all change the titratio
no effect, as it does not affect the concentration/ amount of the sodium hydroxide meaning it will not effect the titration
