H2 Chemistry Paper 1 (Fri, 16 Nov 07, 1430-1530)

This is a reminder to students who are sitting for H2 Chemistry Paper 1 (9746/01).

Date: Friday, 16 Nov 07

Time: 1430 - 1530 (1 h)

Venue: Pls refer to notice boards.

Format: 40 MCQs, answer ALL


Comments:

1) Keep track of time. Every 10 questions will take you about 15 min (this is only an estimate!). If a particular question is more difficult, it is alright to spend more than 1.5 min on it. There should be some easy question elsewhere to compensate for the extra time used to solve the difficult question.

2) Students usually panic during the last 15 min, so Q31 to 40 tend to be poorly done. Please keep your cool! Your ultimate aim is to answer more questions correctly. Trying to answer everything may not necessarily earn you a high score, especially if you had not spent enough time understanding the question.

3) Some questions may not specifically ask you to use the Data Booklet. However, it may be helpful to use the Data Booklet if you get stuck at a particular question.

ALL THE BEST!

2007 AJC Prelims Paper 1 FAQs

Explanation for Q1
Amt of Cl2 molecules in 1 dm3 of air at max toleration level
= (0.005 / 10^3) g / (2 x 35.5) g/mol

Amt of Cl2 molecules in 500 cm3 (which is 0.5 dm3) of air at max toleration level
= (0.005 / 10^3) g / (2 x 35.5) g/mol x 0.5

Amt of Cl atoms in 500 cm3 of air at max toleration level
= (0.005 / 10^3) g / (2 x 35.5) g/mol x 0.5 x 2 (because 1 Cl2 molecule has 2 Cl atoms)

No. of Cl atoms in 500 cm3 of air at max toleration level
= (0.005 / 1000) x (1/71) x 6 x 10^23

Explanation for Q3
For He, n(He) = (p1V1)/RT = (2 kPa x 1 dm3)/RT
For Ne, n(Ne) = (p2V2)/RT = (1 kPa x 2 dm3)/RT

Let new total pressure be p (in kPa).

p(1 dm3 + 2 dm3) = [n(He) + n(Ne)]RT
p(3 dm3) = [2 kPa dm3 + 2 kPa dm3]/RT x RT
p = 4/3 kPa

H2 Chemistry Paper 2 (Tue, 13 Nov 07, 0800 - 0930)

This is a reminder to students who are sitting for GCE A Level H2 Chemistry Paper 2.


Date: 13 Nov 07 (Tue)

Time: 0800 h - 0930 (Duration: 1.5 h)

Venue: Please refer to notice boards.

Format: Structured questions (60 marks), answer ALL

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ATTENTION:

(i) Do NOT write anything on the Data Booklet.

Some students scribbled on the Formula List, in PEN, during the Math papers. Very irresponsible!

I hope that no one has scribbled on the Data Booklet during Chemistry Paper 3. If any of your fellow school mates were to be caught using a Data Booklet with scribbles during Chemistry Paper 2 (i.e. the upcoming paper), he/she will be deemed to have cheated. Whoever wrote on the Data Booklet will be guilty of sabotaging your school mate!

For goodness sake, do NOT write anything on the Data Booklet, not even if you use a pencil!

Please check your Data Booklet CAREFULLY before the start of the paper. Ensure there is no scribble.

(ii) Bring your EZ-link card AND entry proof.

Your EZ-link card or IC has a photo of you. Your index number is found on the entry proof. Both documents are required for identification. (Please do not bring the confirmation slip! It does not have the index number!)

(iii) Check your exam schedule (which is printed on the entry proof).

Sleep early and wake up early. Several students were late for their papers. This is YOUR exam. Be responsible!

(iv) Give yourself EXTRA travelling time, especially on rainy days.

Traffic jams are very common during morning peak hours. The situation worsens on rainy days. Do come to school early.

(v) (Try to) Answer Nature's call before entering the exam hall.

Some students sacrifice precious time (which could be utilised for answering questions) to visit the washroom. For every 1.5 min you stay in the washroom, you are flushing away 1 mark! In addition, you will have to wait for your turn if someone else is already in the washroom. If the call is very urgent, you will get distracted easily and your performance will be affected. Why penalise yourself?

J2s, All the best for the A levels!!