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Edexcel GCE AS Chemistry Unit 1: 22nd May 2015 + Unit 2: 02nd June 2015

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It was definitely exothermic. The forward overall reaction was endothermic and that was already drawn on for us and we had two exothermic enthalpies: -18.8 and -196.8.

Yay that makes me so happy thank you! I thought I got that whole thing wrong+ I remember writing -196.8 but where did that value come from?

Reply 1581

gabby07

Original post by C0balt

Maybe
What I'm saying is because the ions are colorless how would you see the ions moved =ionic binding proof

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Wouldn't you see bubbles of hydrogen and greenchlorine gas?

Reply 1582

JMediGirl

Yes it did and i said that too

Reply 1583

Guitardude165

Original post by HopefulDentist..

Yay that makes me so happy thank you! I thought I got that whole thing wrong+ I remember writing -196.8 but where did that value come from?

The value for -196.8? They gave it in the part before to calculate the minimum mass of CaO required.

Reply 1584

Supermanxxxxxx

For the cyclopentane I put pentene guessing that's wring

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Reply 1585

HopefulDentist..

Original post by Guitardude165

The value for -196.8? They gave it in the part before to calculate the minimum mass of CaO required.

So which was the value we had to calculate?

Reply 1586

kyraaalm

Original post by MoHoosen9167

I got: +178 for the calculation; and also 3.73g for the minimum mass of CaO

I got that but everyone was telling me I calculated both things wrong. So worried about this exam :frown:

Reply 1587

Shaz xx

Just a thought - is mgcl2 aqueous or solid at room temp, cos for the state symbols I put aq but I'm not sure now?!

Reply 1588

Supermanxxxxxx

Original post by Shaz xx

Just a thought - is mgcl2 aqueous or solid at room temp, cos for the state symbols I put aq but I'm not sure now?!

Aq makes a salt

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Reply 1589

Supermanxxxxxx

Anyone made a unofficial Mark scheme need to see how baDly I failed

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Reply 1590

Shaz xx

So was it right to put aq? Cos it came up twice - once in the multiple choice and then when we had to do the Hess law question?

Reply 1591

sj97

Original post by Supermanxxxxxx

Aq makes a salt

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What did you get for the naming the organic compound multiple choice? I put 2-ethyl-4-methylpentane.

Reply 1592

Supermanxxxxxx

Original post by sj97

What did you get for the naming the organic compound multiple choice? I put 2-ethyl-4-methylpentane.

I got hexane

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Reply 1593

sj97

Original post by Supermanxxxxxx

I got hexane

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And when doing the Hess's Law calculation, did you put CaCl2 as a solid?

Reply 1594

C0balt

Original post by gabby07

Wouldn't you see bubbles of hydrogen and greenchlorine gas?

I forgot everything about GCSE. ggwp cobalt

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Reply 1595

Guitardude165

Original post by HopefulDentist..

So which was the value we had to calculate?

Wait what? I'm confused XD The thing we had to calculate was the minimum mass of CaO needed to get that enthalpy value (-196.8). Then we had to calculate the enthalpy change from the hess cycle.