Chemistry paper 61 answers

[mido4help]

First question was easy
The heat position is under solid and postion of water is inside tube
Purpose of ice is to condense water vapour
Test on purity was boiling or melting point of water( 100 C , 0 C )

Second question
Variable to be constant was volume of HCL or temperature or time intervals or apparatus
Connect points in best fit line leaving two close points
Why not all points on same line because mistakes while taking time and inaccuracy in taking volume of sodium thiosulfate
As temperture increase, molecules gain more KE so more sucessful collisons rising up rate
The other graph will steeper ( above) line best fit

Third question
Chromotraphy
water
B was bese line
The conclusions were C has 4 sweet and D has 3 sweets. Both has one identical sweet and others are different of varying solubiles

Fourth question
The differences reading were 32 and 16
oxygen gas
Purple to pink
No need for indicator because potassium managette will change by itself
Volume in Exp 1 is double of in Exp 2
Liquid in experiment 2 is double of concentration of in experiment 1
8 because half volume of hydrogen peroxide
Adv, of measuring cylinder is quick and disadv. is not accurate as burette

Fifth question ( hardest question )
Colorless solution
No obesrevational change
Yellow precipate is formed
Hydrocarbon and alkane

Sixth question
Calculate the difference between volumes given
Plot points and draw increasing line then plateau
5 CUBIC CENTIMETERS

Last question
Bring pH meter and reading will be 13 ( or use universal indicator giving its color)
Fizzing drinks have acids which react with it giving chlroine which is toxic
To clean it from acids and other things
Apporach damp red limtus paper and result it bleaches

These are the accurate answers which will be likely similar to mark scheme
I had only lost 2 marks

 

[Dooouuu]

hey .. i used for the test of the chlorine...... add nitric acid and the AgNO3 ... will give white ppt .... its right ??......
and i write instead of chromatography ... chromatogram ( SILLY MISTAKE ) ...it will be right ??

 

[haochen]

the third question :
B was the base/origin/datum line
"u wrote bese "

 

[haochen]

hey .. i used for the test of the chlorine...... add nitric acid and the AgNO3 ... will give white ppt .... its right ??......
and i write instead of chromatography ... chromatogram ( SILLY MISTAKE ) ...it will be right ??

itll be alright as long as it is the right test
and about the chromatogram ......
srry to say but i dont think its correct


the forth question:
the color change is from colorless to pink coz it said in the flask
so hydrogen peroxide is colourless then it turn pink
(i wrote purple to colorless )

 

[Dooouuu]

i wrote from colorless to pink :S

 

[drugdealer]

Sixth question
i am sure it was 4.9cm cube not 5cm cube
plzzzzzzzzzzz replay

 

[haochen]

Sixth question
i am sure it was 4.9cm cube not 5cm cube
plzzzzzzzzzzz replay

yeah its 4.9 depending on how u draw the two straight line
hope ur satisfied

 

[mido4help]

From the graph, the graph was 5 but I think limits of accuracy. :beer:

 

[haochen]

they said from the graph

 

[phro5031]

I WROTE FROM PURPLE TO PINK , AND 4.9 CM3 , AND TEST FOR SODIUM HYDROXIDE , TO ADD COPPER 2 IONS , WHICH WOULD GIVE BLUE PPT. , IS THAT RIGHT???

 

[PUSHPAK1321]

Fifth question;

I guess two interpretations seems to be correct
Hydrocarbon and alkane
Hydrocarbon and alcohol (ethanol)

 

[nightowl]

I wrote alkane .. but many people says its ethanol ....

 

[Ashique]

I wrote it should be colorless to purple :S Anyways lost around 4-7 marks.. is that bad?

 

[PUSHPAK1321]

It is colourless to purple but I dont think curve will be more than 50/60 an A.