Edexcel IGCSE Chemistry Paper 2C-4CH1 12th June 2019

in fairness so was I until about ten mins ago lol

yea i did the last question i was just panicking that there was like a proper titration based question with having to write steps. but thanks for replying, i was just a bit mixed up

Reply 61

LiamGor

12

yea it was a weird paper, no electrolysis and no longer question - it was easy for me to get a bit paranoid haha

Original post by joejoeeames

in fairness so was I until about ten mins ago lol

Reply 62

Suley143

7

Nitrogen reacts with oxygen at high temperatures inside the car engine, oxides to form nitrogen oxide. Nitrogen oxide is acidic and dissolves in clouds in the air to form an acidic solution. It then rains down as acid rain.

Original post by joejoeeames

you could say something like --> nitrous oxides dissolve into the water in atmosphere forming dilute nitric acid causing acid rain that can affect soil acidity levels and therefore kill wildlife

Reply 63

mp99

10

I said the ethanol will turn into ethanoic acid, but only ethanol is wanted. I didnt mention microbial oxidation

Reply 64

Suley143

7

Alloy is mixture of 2 different metals.

Metals in an alloy have different sized atoms which breaks up the normal lattice structure and makes it harder for layers of atoms to slide over one another when a force is applied.

The yeast break down glucose using a biological catalyst called enzyme to form the ethanol. If oxygen was present the yeast will break down glucose to form carbon dioxide and water instead.

Original post by Roynull

What was alloy one answer?
And why air must be prevented from fermentation??

Reply 65

Mumu123

7

Thats wronf, the reason why you dont want oxygen is to prevent the ethanol from turning into ethanoic acid.

Original post by Suley143

Alloy is mixture of 2 different metals.

Metals in an alloy have different sized atoms which breaks up the normal lattice structure and makes it harder for layers of atoms to slide over one another when a force is applied.

The yeast break down glucose using a biological catalyst called enzyme to form the ethanol. If oxygen was present the yeast will break down glucose to form carbon dioxide and water instead.

Reply 66

AnythingWorks

10

Actually both work. If oxygen is allowed in system after Fermentation began, Acid forms. If it is allowed before, Water and co2 form.

Original post by Mumu123

Thats wronf, the reason why you dont want oxygen is to prevent the ethanol from turning into ethanoic acid.

Reply 67

leo1233

8

For the reactivity one, was it wrong to put do electrolysis in the aqueous solution and test the gas produced at the anode for bromine/chlorine and the least reactive halide will be produced? or have I just ovetconplicated it completely

Reply 68

mp99

10

Just do displacement and see colour change. Yours might be right though

Original post by leo1233

For the reactivity one, was it wrong to put do electrolysis in the aqueous solution and test the gas produced at the anode for bromine/chlorine and the least reactive halide will be produced? or have I just ovetconplicated it completely

Reply 69

Suley143

7

I put to mix both into a beaker. Chlorine is more reactive than bromine and will displace it from its compound to form potassium chloride and bromine as a single free element. The solution would darken to orange as bromine dissolves.

Original post by leo1233

For the reactivity one, was it wrong to put do electrolysis in the aqueous solution and test the gas produced at the anode for bromine/chlorine and the least reactive halide will be produced? or have I just ovetconplicated it completely

Reply 70

Alaa_Abdelhamid

11

Would I lose a mark of I said that alloys are a mixture of a metal and another metal or carbon that are chemically combined

Reply 71

Suley143

7

Alloy is a mixture of 2 or more metals. Your answer is correct also.

Original post by Alaa_Abdelhamid

Would I lose a mark of I said that alloys are a mixture of a metal and another metal or carbon that are chemically combined

Reply 72

Alaa_Abdelhamid

11

And what did I guys write for the one about chlorine and potassium bromide

Reply 73

zara11413

9

i did the same method but i said add silver nitrate and nitric acid to test for ion colours

Original post by Suley143

I put to mix both into a beaker. Chlorine is more reactive than bromine and will displace it from its compound to form potassium chloride and bromine as a single free element. The solution would darken to orange as bromine dissolves.