Year 12s: what will be the first way you research your future options? >>

Edexcel Chemistry IGCSE 1C Unofficial Mark Scheme 19th May 2016

Scroll to see replies

Reply 140

MattB_

If it would form calcium carbonate, water is also formed, but in the diagram there was only 1 product

Reply 141

conradliebers

Original post by grace_wh

I don't think it was, in my opinion, I think I put calcium carbonate.

The answer was calcium carbonate. It's the simple test we learnt where you bubble CO2 through limewater Ca(OH)2 to form a solid precipitate of CaCO3.

Reply 142

DontSweatIt

6d said "max temperature rise", not "max temperature" - thus its 10 degrees.

Reply 143

MattB_

Original post by DontSweatIt

6d said "max temperature rise", not "max temperature" - thus its 10 degrees.

I agree, 10 degress was the maximum temperature rise and so should be the answer

(23 degrees with no solution, and 33 with solution)

Reply 144

DCFGHVBJNKJM

Does anybody know the answers for the Calcium carbonate ones with the 3 answers?

Reply 145

conradliebers

Original post by DCFGHVBJNKJM

Does anybody know the answers for the Calcium carbonate ones with the 3 answers?

Its on my mark scheme I think - CaO, something chloride (can't remember), CaCO3.

It's 4 dyes

Original post by conradliebers

Its on my mark scheme I think - CaO, something chloride (can't remember), CaCO3.

also for the calcium reaction was it fizzes and an orange flame?

Reply 148

sneaky beaver

Original post by MattB_

It depends on the difficulty of paper 2. If paper 2 is of a similar difficulty I would imagine the grade boundary to between 137-140 (out of 180)?

I think the calcium carbonate one was:
Calcium oxide
Calcium chloride
Calcium hydrogen carbonate (a question later in the paper basically gave this answer away)

Yeh i found that, i originally put calcium carbonate, but then changed because i saw the later question. The first one was calcium oxide, which most people got, but that was also given away in the question about the 3 equations, as all 3 decomposed in potassium oxide, so it was easy just to have any <metal> then oxide

Reply 149

alic12345

what did you put for why the results of experiment y were different from experiment x??

Reply 150

DCFGHVBJNKJM

What was the one with the calcium reaction ? fizzing and orange flame?

Reply 151

conradliebers

Original post by -Max-

Thanks for this!

Very welcome.

Reply 152

MattB_

Original post by DCFGHVBJNKJM

What was the one with the calcium reaction ? fizzing and orange flame?

I put effervescence (fizzing) and that the calcium solid disappears as an aqueous solution is formed

Reply 153

conradliebers

Original post by DCFGHVBJNKJM

What was the one with the calcium reaction ? fizzing and orange flame?

There is more than one answer but I wrote it eventually disappears, and it floats on surface of water.

Reply 154

DCFGHVBJNKJM

Original post by MattB_

I put effervescence (fizzing) and that the calcium solid disappears as an aqueous solution is formed

Was it added to HCl or water?

Reply 155

Siddhantss

Guys is there a unoffical mark scheme for qp 42 and 12

Reply 156

conradliebers

Original post by DCFGHVBJNKJM

Was it added to HCl or water?

Water

Reply 157

sneaky beaver

Original post by Abodee1

Was it 4 or 3 dyes?

4 dies i think

Reply 158

DrPeter

Starting topics for Paper 2 then

The whole of electrolysis;
Molten - maybe too easy so they'll leave this (unless calculation involved)
Aqueous
Metal Extraction (usual Qs - cryolite, replacing electrodes)
Ionic half equations
Brine
Faradays
Coulombs

Crude oil, leading to cracking, then to polymers (condensation).

Giant structures.

It will be more challenging, but it's only an hour