In less than 22 days to 2009 GCE ‘O’ Levels Examinations in Singapore, we have seen a surge in the number of students sending us emails on questions that they find challenging. If you have following this chemistry blogsite for awhile, you would also noticed the number of participation in the chemistry questions and the discussions going on. I am glad students are taking actions! anyway, with less than 22 days to GCE ‘O’ Levels Exams, if they do not take actions now – then when!?!?!!

Let’s check out a series of multiple choice questions (MCQs) that were sent by my own chemistry students (under the weekly Ultimate Leap Programme). I have seen several students sending me similar questions lately but to be frank – they are not difficult to handle – but you do need to understand and know the basic essential concepts of those chemistry topics.

Let’s check out the email by this student:

Question 1:
Which compound contains both ionic and covalent bonds
a) sodium carbonate Na2CO3
b) Magnesium bromide MgBr2
c) dicholoromethane CH3Cl2
d) ethanoic acid CH3COOH

i forgot if i have learn this or learn how to find.

&

Question 2:
Compound X contains fluorine and one other element. Which of the following properties of X indicates most clearly that bonds in X are ionic
a) X conducts electricity when molten
b)X does not conduct electricity when molten
c) X is almost insoluble in water
d) X is a crystalline solid at room temperature

why is d not the answer D:

&

Question 3:
Which of the following reactions involving substance X does NOT indicate that X is an acid
a) X + KOH –> heat evolved
b) X + CuO –> salt and water
c) X + Fe –> H2 evolved
d) X + NH4Cl –> NH3 evolved

Is A the answer?

&

Question 4:
In which of the following cases would there be NO observable changes when gas X is reacted with aqueous solution Y?

Gas X                      Solution Y
a) CO2                       Calcium hydroxide
b) Ammonia              Hydrogen Chloride
c) Sulphur Dioxide    Acidified potassium dichromate (VI)
d) Chlorine                Iron(II) Sulphate
How to approach this type of questions to get the correct answer?

In the next blogposts, i will share with you more tricky Chemistry Examination Questions.

PS: if you have been studying very hard for your chemistry, but have yet to score the marks you deserved – it may be due to the fact that your concepts of chemistry are not crystal clear yet i.e. there are misconceptions (and thus mistakes and errors) that prevents you from scoring! You may not be answering to what the examiners are looking out for also – which are key words or phraes! The book i wrote last august Up Your Chemistry Grades Now will be able to address it.

PPS: If you usually fared well for your Chemistry Written Papers (Paper 2) but not your Multiple Choice Questions (MCQs Paper 1), it might be either your concepts (not strong) or exam strategies that causing it. Our last Chemistry Workshop (Score 100% Chemistry MCQ Mastery Workshop) in 2009 will be able to address this.

Stay Tuned for more! =)