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Higher Chemistry 2010 Answers Thread -

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Reply 40

PurpleBin

justasmalltowngirl

what was ur answers to the first one? about the bonding in lithium and boron and nitrogen?

Metallic, covalent, network, discrete molecular.

Reply 41

AyuuBB

Lithium - Metallic lattice
Boron - Covalent network
Nitrogen - Covalent molecular

Reply 42

lilshan

bronwyn93

Did anybody get cyclohexane as one of their answers?

no i had cyclohex-1-ene
i think its for the same one .. it doesnt decolourise bromine? but mine was a shot in the dark haha ....

Reply 43

garlicbreadman

bronwyn93

Yeah

Reply 44

ruairidhe

garlicbreadman

Did anyone get that 0.0003125 moles of oxygen is dissolved in the (ocean) water sample?

i did what did you get for the question 16 a) about two things that would make the experiment more acurate ? i put rough titration at the beginning and repeat the experiment until the results are within a reasonable range

Reply 45

PurpleBin

lilshan

no i had cyclohex-1-ene
i think its for the same one .. it doesnt decolourise bromine? but mine was a shot in the dark haha ....

Wouldn't cyclohex-1-ene decolourise bromine water because it is unsaturated? Only 2 hydrogen atoms were removed so there would be 12 hydrogen left. (c6h12)

Reply 46

garlicbreadman

ruairidhe

I put rinse the burette several times and place a white tile underneath the flask to make the colour change more visible. :confused:

Hope they're ok

Reply 47

bronwyn93

For multiple choice I got...

BCCBB ADCAB DADDA BAAAB CCACA DDCDB BADAB BBDDA

I always do badly on mc though :frown:

Reply 48

AyuuBB

ruairidhe

My answers were

1. Read burette at eye level
2. Remove funnel before titrating

Reply 49

lilshan

afshooneh

what about the % yield? i got 60 something :-S

saaaaame!!!! :yes:

i got 65.5% or something likethat.

Reply 50

PurpleBin

ruairidhe

If you read the answering scheme for 2004 16bi I think its the same question. I don't think those two are on it but I'm not entirely sure.

Reply 51

misterpip

I got 67% for the percentage yield and 0.00031 moles or something for the oxygen in ocean water one. What did everyone get for the Hess's law one about glycerol?

Reply 52

bronwyn93

garlicbreadman

I put rinse the burette several times and place a white tile underneath the flask to make the colour change more visible. :confused:

Hope they're ok

I put place a white tile beneath the flask and swirl the flask

Reply 53

lilshan

PurpleBin

Wouldn't cyclohex-1-ene decolourise bromine water because it is unsaturated? Only 2 hydrogen atoms were removed so there would be 12 hydrogen left. (c6h12)

im not sure , my numbers for each carbon and hydrogen worked out but i wasnt sure if it decolourised it or not. standard grade seems so far away haha

Reply 54

CraigR1845

i just wrote "polyethenol is soluble"

think they'll give me the mark even though i didn't say in water :frown:

Reply 55

garlicbreadman

bronwyn93

For multiple choice I got...

BCCBB ADCAB DADDA BAAAB CCACA DDCDB BADAB BBDDA
BCCBB DCBAD BABDD CAAAB CDACA DDCDD BABCB CBDAA

I always do badly on mc though :frown:

Got 13 different from you

Reply 56

Farwa

does any know how they found the ionisation energy for the first electron for ... helium was it?? dont remember the element :\

Reply 57

PurpleBin

For 2004 16bi which was a similar question the possible answers were:
Flask should be swirled
Read burette at eye level
White tile under flask
White paper behind burette for easier reading
Titrate slowly
Add solution dropwise (near end-point)
Remove funnel before taking initial burette reading
Keep washing flask down.

Reply 58

garlicbreadman

misterpip

I got 67% for the percentage yield and 0.00031 moles or something for the oxygen in ocean water one. What did everyone get for the Hess's law one about glycerol?

-672kJ/mol I got

Reply 59

bronwyn93

misterpip

I got 67% for the percentage yield and 0.00031 moles or something for the oxygen in ocean water one. What did everyone get for the Hess's law one about glycerol?