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EDEXCEL GCSE Chemistry Paper 2 12th June 2019 Unofficial Markscheme

ionic solid- high boiling points
Ti - 4+
10^-7m
reflects harmful UV, or transparent so doesn't leave white marks
could catalyse harmful reactions due to high surface area to volume ratio?

kerosene - aircraft fuelSubmit reply

diesol oil - cars and trains
lower viscosity, higher ease of igntion etc

But did it not ask for the physical property

Reply 21

IsMo987

12

I wrote that they are strong does that count

Reply 22

sdknergreg

4

6 markers:

When size decreases but conc stays the same volume of gas is higher due to there being larger SA:V ratio. this means the particles around it will have more area to work on increasing rate of reaction etc

When size is constant but conc differs, volume of gas increases with higher conc. this is because there are more particles in the same amount of space increasing the chance of a collision of particles and therefore rate of reaction.

other 6 mark:

Aliminium test. Add excess NaOH to differentiate it from caclium ions. it will turn colourless.

Ammonium test. Damp red litmus paper turns blue

Sulfate test. Add dilute HCl and barium chloride. white precipitate forms.

(think most of this is right)

Reply 23

smith.214

8

I got 6.92 aswell

Original post by Dayo03

I swear it was 6.92

Jyhh

Reply 24

Sambo1725

6

I did same

Original post by IsMo987

I wrote that they are strong does that count

Reply 25

hehe_x

14

that was a pretty easy test ngl - grade boundaries are gonna be high

It's 10^-9 btw

Original post by hehe_x

that was a pretty easy test ngl - grade boundaries are gonna be high

I think 165 for a 9

Reply 28

hehe_x

14

it's not. 100 nanometres is 10^7

Original post by Sambo1725

It's 10^-9 btw

Reply 29

Aceaceace21

2

Original post by Sambo1725

What mass of magnesium oxide is made ? Near front of paper I got round 2.24 or somet

Howww

Reply 30

Adedayo2003

14

6.92 for lithium empirical formula

2.25 for mass on MgO

4 + (for the charge)

1x10^-7 for 100 nm

hydrobromic acid - when HBR dissolves in water

the table one was about halogen displacement reactions - iodine is less reactive so gets displaced

6 marker on collision theory :
Concentration: If there is more of a substance in a system, there is a greater chance that molecules will collide and speed up the rate of the reaction. If there is less of something, there will be fewer collisions and the reaction will probably happen at a slower speed.
Increasing the surface area of a solid reactant exposes more of its particles to attack. This results in an increased chance of collisions between reactant particles, so there are more collisions in any given time and the rate of reaction increases.

Nanoparticles do not leave a white mark on the skin - good for sunscreen
however, there hasn't been much research so we don't know long term effects

unsaturated means double bond so can still react with other elements as bond breaks up

in bromine water ethene turns it colourless , poly ethene no as it doesn't have a double bond

kerosene - used for aircraft

kerosene compared to diesel oil - easy ignition, less viscous, low boiling point etc

the one about the Molecular formula for CH2 was C6H12

Test for chlorine - blue litmus paper turns red then bleaches white

1.5 x 10^21 for the avogadros contant question

In the production of ethanol - can't be 80 degrees or yeast gets denatured

To get the mass of the alcohol needed to change the temp of water: light spirit burner and wait for of water to change by 20 degrees then reweigh the spirit burner and calculate the change in mass

82.7 for carbon in butene

lithium is less reactive than potassium because it has less shells so it would be harder to lose the electron as there is a stronger force of attraction between the nucleus and the outer electron

butane and pentane are neighbours because they differ by a CH2 unit

CO2 levels change due to burning fossil fuels (not always the same amount of co2 released)
deforestation and afforestation (dk if this is right tho)

electron configuration for NaCl after reaction was:
Na - 2.8
Cl 2.8.8

for exothermic - energy used to form bonds > energy used to break bonds - overall negative energy change

colour and state of astatine - black and solid

I can't remember the hydrocarbon (think it was Ethane or ethene ) - it produced CO2 and H20 - then had to balance it

(edited 4 years ago)

Reply 31

IsMo987

12

What did people write for why they were neighbours I think for the propane and butane

Reply 32

Aw2003

1

High boiling point
Ti4+
Nanoparticles make see through sunscreen that reflects uv rays
Dangerous because easily absorbed by the body and don’t know long term health risks?
2.25g
82.7 or something for carbon in butene
C6H12

Reply 33

Maryam9900

What did everyone get for the calculations?

Reply 34

smith.214

8

Theu different from each other by CH2 so they re neighbours. Same homologous family they have general formula cnh2n+2

Original post by IsMo987

What did people write for why they were neighbours I think for the propane and butane

Reply 35

IsMo987

12

Original post by smith.214

Theu different from each other by CH2 so they re neighbours. Same homologous family they have general formula cnh2n+2

Do you think I’ll get a mark if I said they were from the same functional group and had similar chemical properties like high boiling
Points

Reply 36

Rhianna&Praise

I got 2.4 for the magnesium oxide one

Reply 37

Aw2003

1

2.25 I think

Original post by Rhianna&Praise

I got 2.4 for the magnesium oxide one

Reply 38

hehe_x

14

yeah, maybe even 167/8

Original post by IsMo987

I think 165 for a 9

Reply 39

smith.214

8

Well I think what you said is more an answer to ' why they are from the same homogolous family'. But don't worry its only 2 marks. I forgot to answer the rubidium question :smile:

)

Original post by IsMo987

Do you think I’ll get a mark if I said they were from the same functional group and had similar chemical properties like high boiling
Points

EDEXCEL GCSE Chemistry Paper 2 12th June 2019 Unofficial Markscheme

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