AQA A2 CHEM4 & CHEM5 June 2015 [official discussion thread]

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What is the value of Kc affected by?
What is the value of k affected by?

Is the answer to both these questions, concentration, pressure and temperature, and catalyst has no effect?

Reply 1781

baffledchick

Original post by Kill3er

What is the value of Kc affected by?
What is the value of k affected by?

Is the answer to both these questions, concentration, pressure and temperature, and catalyst has no effect?

I thought K was only affected by temperature?

Reply 1782

baffledchick

How does everyone find the timing for this paper? What is the best way to do it?

Reply 1783

Ilovemaths96

Original post by Kill3er

What is the value of Kc affected by?
What is the value of k affected by?

Is the answer to both these questions, concentration, pressure and temperature, and catalyst has no effect?

temp alone for both

Reply 1784

adorablegirl1202

Original post by Ilovemaths96

whats the equation page no.?

the example I have in notes is CH3COOH + Na -> CH300-Na+ + H2

Another thing can you or anyone else explain to fat and oils and that bit, it's kinda confusing me - does it always break into propane-1,2,3-triol and some sorta long chain carboxylic acid?

Reply 1785

Ilovemaths96

Original post by baffledchick

How does everyone find the timing for this paper? What is the best way to do it?

some people say start with harder questions and then do easy questions.
Or just go through it in order

Reply 1786

student_anonnn

Original post by Ilovemaths96

spelling it seems :smile:

I meant WEAKKKK OMG that was a total accident im tired ok and I didn't read over !!! im an A grade English student .. haha no but seriously it was an accident. spelling police.

Reply 1787

Ilovemaths96

Original post by adorablegirl1202

put a 2 infront of h2 and its balanced?

yeah i think so but you'll have to verify that

Reply 1788

broconomist

rate = k[NO]2[O2]
Units of k
mol dm-3

is the mark scheme on the specimen wrong there^?

Reply 1789

adorablegirl1202

Original post by Ilovemaths96

put a 2 infront of h2 and its balanced?

yeah i think so but you'll have to verify that

Oh yeah of course well that's easy haha, the notes my teacher gave didn't have it balanced when usually it is so I got a bit confused - thanks!!!

Reply 1790

Ilovemaths96

Original post by student_anonnn

I meant WEAKKKK OMG that was a total accident im tired ok and I didn't read over !!! im an A grade English student .. haha no but seriously it was an accident. spelling police.

lol relax! Chem 4 has that effect haha

Reply 1791

Ilovemaths96

Original post by adorablegirl1202

Oh yeah of course well that's easy haha, the notes my teacher gave didn't have it balanced when usually it is so I got a bit confused - thanks!!!

Reply 1792

Ilovemaths96

so when fats and oils are hydrolysed by NaOH they give propane 1,2,3-triol (glycerol) and a soap right?

Reply 1793

baffledchick

Original post by Ilovemaths96

so when fats and oils are hydrolysed by NaOH they give propane 1,2,3-triol (glycerol) and a soap right?

Yep, and to form biodiesel which is a methyl ester of long carboxylic acid chain is it a triglyceride ester + alcohol gives you glycerol and biodiesel?

Reply 1794

broconomist

is it just me that's finding a tonne of errors in the specimen paper/ms?

Reply 1795

Ilovemaths96

Original post by baffledchick

Yep, and to form biodiesel which is a methyl ester of long carboxylic acid chain is it a triglyceride ester + alcohol gives you glycerol and biodiesel?