The chemistry paper 1 can be categorized as above average and challenging. The questions are very good and are able to test the understanding of the students thoroughly.
Here are a few questions which my students ask about:
Q4. This question is about food packaging. Many students did not choose the answer 'II Release poisonous gases', but when we burn plastic it does gives out toxins. And plastic will not 'Cause the formation of algae'. So the best answer will be C.
Q5. This question is about metal ores. This question will test students memory power and how detailed they memorise the chemistry facts. A good question. Answer is hematite.
Q10. This question is about fats and oils. Its quite tricky as all the answers looks correct if not read properly. the best answer is D as fats are saturated and oil are unsaturated therefore they are chemically different.
Q11. This question is about detergent. Students have to know that detergent is made from sulphuric acid and an alkali.
Q36. This question is about drying agent. I think most student will not know that soda lime can also be an effective drying agent.
Q39 to 49 are mostly calculation questions. The questions are well set and each question can test the students understanding of stoichiometry which is very important for higher level studies.
Please do share and comment your view below.
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just updated the answers 17 is C :)
ReplyDeleteI believe 48 might be a different answer...C
ReplyDeleteZn + 2AgNO3 > Zn(NO3)2 + 2Ag
From the question the mole of zinc nitrate is 0.002
The heat released is 840J
However the ratio of Zn : AgNO3 is 1:2
So the heat of displacement would be -840/-0.001 which is -840kJ
As a prove u take the mole of zinc and multiply ur answer and should get 840J
If the answer is -420kJ multiplying the mole of zinc with it will get 420J
So...what wud be the answer?
Upon deep inspection and researching,
DeleteI can conclude that the answer for 10. Fats and oils is B
According to my sources and even the text book itself pg85
It is stated that fats and oils are chemically very similar
"Fats in animals are solid while fats in plants are liquid and called oils"
Was what was written in the textbook
the fats and oils question has a few answers then.
DeleteFor Question 48, the answer should be C. Heat of displacement = heat released when one mole of metal is displaced from its salt solution by a more electropositive metal right ? One mole of metal# , so by comparing the number of moles the final answer should be C i think
DeleteExactly! :)
DeleteQ48 The answer shd be B. The reason:
DeleteFrom eqn: Zn (excess) + 2 AgNO3 --> Zn(NO3)2 + 2 Ag,
Excess Zn will displace x mole of Ag from x moles of AgNO3.
Since, 20.0 cm3 of 0.1 mol dm-3 of AgNO3 = (20/1000) x 0.1 = 0.002 mol,
This means: 0.002 mol of Ag+ in AgNO3 solution will be displaced by excess zinc to produce 0.002 mol of Ag and
Release heat energy, E = mcÓ¨ = 20 x 4.2 x 10 J = 840 J (per 0.002 mol)
Hence, the Heat of Displacement = - 840 J/0.002 mol =- 420 000 J mol-1
= - 420 kJ mol-1 (Answer B)
Can I get A if I only get 33 in paper1 chemist?
ReplyDeleteit depends how you did for paper 2 and paper 3? :)
DeleteThe empirical formula (no.41) no need find the simplest ratio meh...?
ReplyDeleteI thought need to divide by the lowest number of mole, which is 2 to find the simplest whole number ratio?
Q41 Answer D. Reason:
DeleteMg : N = 72 : 28 = 24 x 3 : 14 x 2. Therefore, Mg3N2. (Answer: D)
Thx sir..
ReplyDeleteHey! can i ask why is no.28 D? my answer is C
ReplyDeleteQ28 Answer D (E, Z, X, Y):
DeleteReason:
...............Y ] – the most electropositive
..............{ X ].... 0.7V
1.4V.......{ Z ] )
..............{ E ) 1.2V – the least electropositive
good illustrations. thanks
DeleteIts sure that all answer is corret?
ReplyDeletepretty sure. which one you are doubtful about?
DeleteSir ,do u have the bio paper 1 spm answer?
ReplyDeletepls refer to our latest post now :)
ReplyDeleteQ10 Answer B.
ReplyDeleteReason: Pl. see Pg 87 of Form 5 Chemistry KBSM Textbook - Fats and oils belong to the same homologous series of ‘ester’ just as methanol and all other alcohols belong to the same homologous series of ‘alcohols’. If methanol can’t be dehydrated into alkene, does that make methanol chemically different from the rest of the alcohols? Similarly, if fats (saturated esters) can’t be hydrogenated while oils (unsaturated esters) can, does that make fats and oils chemically? The answer to this question will decide whether D can also be accepted as a correct answer in addition to B. :))
if paper 1 is challenging , and most student didn't score , will percentage of paper 1 decline ?
ReplyDeleteWhy is the answer for number 49 A ? My answer is D.
ReplyDeleteThe answer for number 40 Should be B. how is it A?
ReplyDeleteYes I agree with you.
DeleteQ40 Answer A. Reason:
DeleteMolar mass of CO2 = [12 + 2(16)] g = 44 g
therefore, 8.8 g of CO2 = (8.8/44) mol of CO2 = 0.2 mole
Molar mass of water (H2O) = [2(1) + 16] = 18 g
3.6 g of H2O = (3.6/18) mol of H2O = 0.2 mole also.
Same mole means same number of molecules,
therefore, answer A.
For question 30, Although it is a weak acid it will still react with the limestones to produce carbon dioxide right? Doesnt it?
ReplyDeleteI have check it with my teacher and she said the answer for 49 is B
ReplyDeleteQ49 Answer A. Reason
ReplyDelete40.0g of NH4NO3 = 40/80 mol of NH4NO3 = 1/2 mole of NH4NO3
= (1/2)(6.02 x 10^23) chemical formula units (particles) of NH4NO3
But, each chemical formula unit of NH4NO3 has 2 nitrogen atoms,
therefore, (1/2)(6.02 x 10^23) chemical formula units (particles) of NH4NO3 has
2 x (1/2)(6.02 x 10^23) number of nitrogen atoms
i.e. 6.02 x 10^23 number of nitrogen atoms (Answer A)
thank you Mr Tan :)
Deleteyou're welcome, Mr. Sai Mun. :)
DeleteBelieve in sharing whenever time permits. :)
oohh this is confusing...
ReplyDeletesir sai mun is it right my teacher said that to get a - in chemistry is 64 above???hope u will reply
ReplyDeleteyes somewhere around there. it really depends on the difficulty of the paper and how the students did in that year. :)
Deletehey ,,i just want to ask ,can i get a+ if i got 44 in paper 1 ? :)
ReplyDeleteanyone has answers for sejarah and mathematics?
ReplyDeleteAnswers for Modern Maths Paper 1 (SPM 2013) are obtainable at:
ReplyDeletehttp://addmathsf45.blogspot.com
:)
do you got answer for science paper 1,perdagangan paper 1 and sejarah paper 1??...anyone hv pls give me the link or page pls.. :3
ReplyDeleterefractive index = sin incident ray(70)/sin refracted ray(40) = 1.5
ReplyDelete