What are the different types of JC Chemistry tuition classes available at your centre?

We have 3 modes of learning for students to choose from: weekly physical classes at Bishan; weekly online lessons via Zoom; and on-demand video lessons.

Are you the only Chemistry tutor conducting the classes or do you engage other tutors to do that?

Please be rest assured that I conduct all my classes personally and I do not engage other tutors to teach at my centre.

How well do your students perform after attending your H2 Chemistry tuition classes?

Most of my students showed improvements by at least 3 grades and more than 80% have attained distinction for A Levels. The earlier the students join my classes, the more confident I am in improving their grades.

What is your class size at Bishan?

Usually the class size is around 10 to 12 students. Max class size is 16 pax.

Is there makeup lesson if I miss a class?

Yes makeup lesson is available in the same week subject to availability. If makeup class is not possible, the student can view the recorded video lessons at Google Classroom.

Do you have trial lesson available? How much is it?

Yes we do. Fees for trial lesson are for Bishan class and for Zoom online class.

Does your centre offer O Level chemistry tuition? Do you teach IB / IP chemistry tuition? How about H1 Chemistry?

Chemistry Guru specialises in H2 Chemistry for JC1 and JC2 or IP Year 5 and IP Year 6 students only. Find out all the information about A Level H2 Chemistry and the detailed comparison between H1 and H2 Chemistry. We do not conduct lessons for H1 Chemistry, O Level Chemistry, IB Chemistry or IP Chemistry at IP Year 3 and IP Year 4.

2023 A Level H2 Chemistry Paper 1 Solutions - Questions 11 to 20

Question 11

2023p1 q11

Answer: D

Topic: Kinetics

Explanation:

When substrate concentration is lower than enzyme concentration, there is enough enzyme to handle the increase in concentration of substrate. Hence rate will be first order with respect to substrate and rate increases as substrate concentration increases.

When substrate concentration is higher than enzyme concentration, saturation occurs where all enzymes are fully utilised so rate of reaction will reach a maximum and stay constant, ie zero order with respect to substrate.

2023p1 q11 explain

Question 12

2023p1 q12

Answer: D

Topic: Chemical Equilibria

Explanation:

Equilibrium constant K is only affected by changes in temperature hence adding catalyst or changing pressure will not change K.

For exothermic reaction, when there is increase in temperature, position of equilibrium will shift left to favour endothermic reaction and absorb excess heat. Partial pressure of reactant will increase while partial pressure of product will decrease, hence K_p will decrease.

2023p1 q12 explain

Question 13

2023p1 q13

Answer: C

Topic: Chemical Equilibria

Explanation:

Let initial partial pressures of N₂ and H₂ be x and 3x. We can then fill up the ICE table to determine equilibrium partial pressures in terms of x.

P(N₂) = (x - 46); P(H₂) = (3x - 138); P(NH₃) = 92

Total pressure is 100 atm hence we can solve for x = 48 and determine equilibrium partial pressures to be

P(N₂) = 2; P(H₂) = 6; P(NH₃) = 92

Finally we can substitute these terms into K_p expression and solve for K_p = 19.6

2023p1 q13 explain

Question 14

2023p1 q14

Answer: C

Topic: Redox Titration

Explanation:

Moles of Br in reactant Br₂ = 0.03; moles of Br in product KBr = 0.025

Hence moles of Br in product BrO_x^- = 0.03 - 0.025 = 0.005

This redox reaction is involving reduction of Br₂ to Br^- (known half equation) and oxidation of Br₂ to BrO_x^- (unknown half equation).

From known reduction half equation, moles of electron gained in reduction = moles of Br^- = 0.025 = moles of electron lost in oxidation.

Mole ratio of electron lost to BrO_x^- = 0.025 / 0.005 = 5 / 1

This means each Br in Br₂ loses 5 electrons to form BrO_x^-, oxidation state of Br is in BrO_x^- is +5, hence x = 3

2023p1 q14 explain

Question 15

2023p1 q15

Answer: B

Topic: Solubility Product

Explanation:

Statement 1 is correct since white ppt silver ethanoate is formed.

Statement 2 is correct since formation of cream ppt silver bromide is favoured. As AgBr is less soluble, a lower concentration of Ag⁺ is needed to precipitate AgBr. As AgBr ppt is formed, Ag⁺ concentration decreases. This will shift the position of equilibrium of dissociation of silver ethanoate to the right hence more silver ethanoate will dissolve.

2023p1 q15 explain

Question 16

2023p1 q16

Answer: C

Topic: Intro to Organic Chem

Explanation:

Propane has 3 sp³ hybridised carbons. Each sp³ carbon has three 2p orbitals hybridised hence total 9 2p orbitals.

Benzene has 6 sp² hybridised carbons. Each sp² carbon has two 2p orbitals hybridised hence total 12 2p orbitals.

Ethyne has 2 sp hybridised carbons. Each sp carbon has one 2p orbitals hybridised hence total 2 2p orbitals.

Therefore total 2p orbitals hybridised = 9 + 12 + 2 = 23.

2023p1 q16 explain

Question 17

2023p1 q17

Answer: C

Topic: Halogenoalkane

Explanation:

For chloroethene, lone pair on Cl can interact with pi bond in ethene hence there is delocalised pi system between carbons and chlorine. There is resonance stability for C-Cl bond therefore chloroethene is unreactive to nucleophiles.

2023p1 q17 explain

Question 18

2023p1 q18

Answer: C

Topic: Intro to Organic Chem

Explanation:

We only need to consider alkene functional groups and ignore cycloalkane since there is no ring structure. Constitutional isomers will also exclude cis-trans isomers.

A systematic permutation is required to figure out the total number of isomers = 5.

2023p1 q18 explain

Question 19

2023p1 q19

Answer: A

Topic: Benzene

Explanation:

X is chlorobenzene since Cl group is 2,4 - directing and can direct nitro group to position 2 wrt Cl to form required product.

Y is benzoic acid since acid group is 3 - directing and can direct methyl group to position 3 wrt acid group to form required product.

2023p1 q19 explain

Question 20

2023p1 q20

Answer: C

Topic: Benzene

Explanation:

Statement A is wrong as benzene undergoes electrophilic substitution.

Statement B is wrong as benzene is stable and does not take part in addition reactions without catalysts.

Statement C is the answer where second step for electrophilic substitution of benzene involves benzene reacting with electrophile to form intermediate.

Statement D is wrong as all the C-C bonds in benzene are equal in length and energy.

2023p1 q20 explain