Edexcel Chemistry unit 2 May 2011 (Exam discussion)

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im so screwed. Screwed up the last question.

The indicator is starch right? Blueblack to colourless? I assume the chlorine will react with the potassium iodide immediately upon adding, thus forming iodine to react with the thiosulphate.. :frown:

And the Ag & HNO3 part, urghhhhh, i wrote H20, then last minute i put H2, instead of H20. :frown:

Couldn't balance the eq. :frown:

So stupid.

Yep indicator right and color right as well :smile:

It was 2H20 I think. (don't exactly remember the equation but it balanced out in the end after 10 serious minutes of substituting random numbers) lol

Reply 41

beelz

Does anyone have the markscheme? If not we should post all the MCQ we remember and answers.
Reaction of Mg and steam? I thought it was Mg(OH)2 but I think it's actually MgO
Trend in Group 2 hydroxide and sulfate further down the group? OH increases, SO4 decreases
Trend in ionisation energy and electronegativity down group 2? Both decrease
Percentage error? 0.4
Product when propan-1-ol and 2-ol oxidised partially? -al and -one
Molecular ion peak? Not sure, I put 3

Reply 42

warkan

Original post by johanmasha

what causes immediate damage to da environment?
is it hcl or da one wid co2?

i put co2 as its a greenhouse gas and contributes to global warming.

Reply 43

Erycuna

Original post by warkan

i put co2 as its a greenhouse gas and contributes to global warming.

i wrote SO2(g) and it lead to acid rain (erosion of building forests etc...)
so is it corrct?

Reply 44

warkan

Original post by Erycuna

lol i told u im not sure of the equation /im not sure if it was a question about NO o.o..
however..it was in the form of X(g)+Y(g)->2Z(g)

lol how many marks was dat question ? :/ How the hell did i manage to read the number of molecules wrong..oh well lol

Reply 45

alz333

and for the last question the answer was 302-203 as the overal reaction

Reply 46

ACatCalledMeow

Original post by Erycuna

i wrote SO2(g) and it lead to acid rain (erosion of building forests etc...)
so is it corrct?

I put SO2 too. But i said it's a greenhouse gas. :mad:

urghhhh

Reply 47

Sailingslipelick

MCQ

1.Reaction of solid Mg with steam. Mg (s) + H20 (g) - MgO + H2
2. Sulfate/Hydroxide solubility. Sulfate decreases down group 2, hydroxide increases
3. Thermal stability of nitrate/carbonate Both increase
4.ionisation energy/electronegativity. I.e. decreases down and electronegativity decreases down
5. Bond angle of BeCl3- 120
6.Bond angle of something else
7. Which molecule is linear?
8.Which molecule is non polar? Ccl4
9. Which molecule is not a greenhouse gas? The one which was something 2. maybe N2
10. Mass spectrum. I think answer was 3 (c). b/c 79-79 81-81 and 79-81
11. Hydrogenation. Addition and reduction. I think, please correct if wrong.
Series of equation
12. Which has an atom economy of 56% - B
13. Which produces a gas which has immediate effect on the environment? I put Hcl
14. Reacting CH3Br with ammonia (in ethanol). What product would not form? I think it was C- dimethyl something
15. Percentage error. 0.4%

Section B

Colour of chlorine in water
Reacting chlorine with potassium iodide solution. Colour in solution.
Ionic equation of chlorine vs. iodide ions
Indicator used and colours. 1% starch solution. Blue black-colourless
Ionic equation of iodine and thiosulfate ions. I2 + 2S203 2- -> 2I- + S406 2-
Moles- a few marks-cant remember the nitty gritty.
What is observed when reacting Cl2 with H2so4?
Why?
What reactant do you use to turn an alcohol into a chloronoalkane? PCl5
Reaction with Na. Suggest one thing you would see?
Diagram

Ethanethiol question.
Dot and cross diagram
Bond angle around Csh and why? Two lone pairs, two bond pairs. Repel each other to a position of max sep/min rep. 104.5?
Why is 0H0 180 degrees?

"some q's here cant remember'
Suggest formula of reagent used to convert halogenoalkane to ethanethiol?
Gas produced with ethanethiol-but not an alcohol. So2 and why it is bad?Acid rain.

Section C

Suggest dot and cross of no
Ag and HN03-balancing Wasnt it: 3Ag + 4HNO3 - NO + 3AgNo3 + 2H2O
Pressure question on yield -same no. of moles
pressure question on rate of reaction. ( I thought this was increasing pressure)
NO on jet engines and cars
NO equations (3) and then mentioning 2moles of O3 to 3 moles of O2, No is a catalytical radical, blah blah.

Missed out quite a few, but feel free to copy and paste and fill in the gaps, as Im not going to be here today.

(edited 12 years ago)

Reply 48

warkan

Original post by Erycuna

i wrote SO2(g) and it lead to acid rain (erosion of building forests etc...)
so is it corrct?

But none of the equations had so2 as a product? right ?

(edited 12 years ago)

Reply 49

Erycuna

Original post by ACatCalledMeow

I put SO2 too. But i said it's a greenhouse gas. :mad:

urghhhh

well SO2 is a green house gas >.>

Reply 50

beelz

Can anyone remember the subquestions for the question about KCl reacting with H2SO4 in a test tube?

Reply 51

ACatCalledMeow

Oh, what did all of you wrote for the effect of lower pressure to the rate of reaction?( The effect on equlibrium is none right since the number of moles are equal..?)

I said at lower pressure, there will be less number of molecules per unit volume. So, less collision between the molecules, meaning less number of successful collision. Thus, decreasing the rate of reaction. is it correct? :s-smilie:

Reply 52

ACatCalledMeow

Original post by Erycuna

well SO2 is a green house gas >.>

is it??? :O I thought it's only a gas that causes acid rain. :frown:

Reply 53

Erycuna

Original post by ACatCalledMeow

yes Meow both r correct ^^

Reply 54

Erycuna

Original post by ACatCalledMeow

is it??? :O I thought it's only a gas that causes acid rain. :frown:

lol it turned out not to be a green house gas ,i jst googled it out T_T

Reply 55

ACatCalledMeow

Original post by Erycuna

lol it turned out not to be a green house gas ,i jst googled it out T_T

Me too

Sad sad day for me. Sigh. So many questions.. Ahhhh :frown:

Reply 56

sarahinuae

The moles were equal on both sides:
N2 + O2 = 2NO
And i thought that peak question said the parent ion peak, which there is only one, so i put 1.
What did everyone get for the conc of whatever in the calculation question?
I drew a distillation.
And i couldn’t balance water so i put NH3, but couldn't balance that either. :s-smilie:

Reply 57

alz333

didnt the question say if you increase pressure on the for rate of reaction