# Chemistry as level cie m/j 2019 paper 21

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#1
Did anyone take this paper? How did you find it? Let’s discuss answers below
0
2 years ago
#2
The exam was really easy ... What did u get for the Mass of chlorine ... I got 0.1158 = 0.116 but all my other friends got something different because when u find moles = pv/rt then I multiplied by 35.5 all my other friends multiplied by 71 .. All whats ur similarities in the first q of X and the group twos ... I said that they both have the same oxidation state ( 2) and their carbonattes decompose the same way forming metal oxide and co2 ... and the difference.is that group 2 oxide is white while x oxide is black
0
2 years ago
#3
(Original post by john wick pro)
The exam was really easy ... What did u get for the Mass of chlorine ... I got 0.1158 = 0.116 but all my other friends got something different because when u find moles = pv/rt then I multiplied by 35.5 all my other friends multiplied by 71 .. All whats ur similarities in the first q of X and the group twos ... I said that they both have the same oxidation state ( 2) and their carbonattes decompose the same way forming metal oxide and co2 ... and the difference.is that group 2 oxide is white while x oxide is black
you were supposed to find the number of chlorine atoms. so you use the same mass and divide it by 35.5 to the number of moles and times it by 6.02*10^23 that’s what i did
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#4
(Original post by john wick pro)
The exam was really easy ... What did u get for the Mass of chlorine ... I got 0.1158 = 0.116 but all my other friends got something different because when u find moles = pv/rt then I multiplied by 35.5 all my other friends multiplied by 71 .. All whats ur similarities in the first q of X and the group twos ... I said that they both have the same oxidation state ( 2) and their carbonattes decompose the same way forming metal oxide and co2 ... and the difference.is that group 2 oxide is white while x oxide is black
For the mass of chlorine I multiplied by 71 and got 0.232g
For similarities and differences I wrote that too
What did you write for the organics 8 mark table question? One with tollen’s reagent
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#5
(Original post by IntelligentAngel)
you were supposed to find the number of chlorine atoms. so you use the same mass and divide it by 35.5 to the number of moles and times it by 6.02*10^23 that’s what i did
Yep exactly, I did that too
0
2 years ago
#6
(Original post by Sudee)
Yep exactly, I did that too
Star ⭐️
0
2 years ago
#7
(Original post by Sudee)
For the mass of chlorine I multiplied by 71 and got 0.232g
For similarities and differences I wrote that too
What did you write for the organics 8 mark table question? One with tollen’s reagent
for the tollens reagent i wrote the letter of the aldehyde (B i think) and then the observation o wrote Silver mirror (Silver metal)
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#8
(Original post by IntelligentAngel)
Star ⭐️
What did you write for the organics 8 mark table question? (the one with tollen’s reagent, alkaline iodine etc)
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#9
(Original post by IntelligentAngel)
for the tollens reagent i wrote the letter of the aldehyde (B i think) and then the observation o wrote Silver mirror (Silver metal)
Yeah, and for alkaline iodine I wrote the one with ketone A and yellow precipitate
For sodium I wrote c,d and effervescence as observation
0
2 years ago
#10
(Original post by Sudee)
Yeah, and for alkaline iodine I wrote the one with ketone A and yellow precipitate
For sodium I wrote c,d and effervescence as observation
For the iodine one i wrote A and D cause D also has the CH3CO group and then for the sodium i only wrote C lol😂 but yeah my observations are the same
0
2 years ago
#11
(Original post by Sudee)
Yeah, and for alkaline iodine I wrote the one with ketone A and yellow precipitate
For sodium I wrote c,d and effervescence as observation
no no no i’m wrong for the carboxlyic acid. It’s not used to test for them😂
0
2 years ago
#12
(Original post by IntelligentAngel)
you were supposed to find the number of chlorine atoms. so you use the same mass and divide it by 35.5 to the number of moles and times it by 6.02*10^23 that’s what i did
This is for part b yeah
0
2 years ago
#13
For tollens Only the ketone and a silver mirror is formed as observation ... in Alkaline iodine only the aldehayde ... and yellow ppt ... in Na. Metal only carboxylic acid and alchol ... and White solid is formed
(Original post by IntelligentAngel)
For the iodine one i wrote A and D cause D also has the CH3CO group and then for the sodium i only wrote C lol😂 but yeah my observations are the same
0
2 years ago
#14
(Original post by john wick pro)
For tollens Only the ketone and a silver mirror is formed as observation ... in Alkaline iodine only the aldehayde ... and yellow ppt ... in Na. Metal only carboxylic acid and alchol ... and White solid is formed
only the aldehyde reacts with tollen
0
2 years ago
#15
(Original post by john wick pro)
For tollens Only the ketone and a silver mirror is formed as observation ... in Alkaline iodine only the aldehayde ... and yellow ppt ... in Na. Metal only carboxylic acid and alchol ... and White solid is formed
i think that’s observation is meant to be efferevsense or bubbles because of the hydrogen formed
0
2 years ago
#16
Lol yh sorry I meant to write the aldehayde .. I wrote the aldehayde in the exam but I miss typed
(Original post by IntelligentAngel)
only the aldehyde reacts with tollen
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