Community

You need to log in to create posts and topics.

Chemistry (9701) June 2017 Paper 12 [SOLVED]

1)
Option A: protons = 9 neutrons = 9 electrons = 10
Option B: protons = 11 neutrons = 12 electrons = 10
Option C: protons = 15 neutrons = 16 electrons = 15
Option D: protons = 16 neutrons = 16 electrons = 18

Hence, the right option where all are different is B.

Uploaded files:
  • Capture.JPG

2)
Option A:

moles of O in 0.25 mole of Al2O3 = 0.75
number of oxygen atom = 0.75 * 6.02 * 10^23 = 4.515*10^23

Option B: SO2,

moles of O in 0.75 mole of SO2 = 1.5
number of oxygen atom = 1.5 * 6.02 * 10^23 = 9.03 * 10^23

Option C:

moles of O in 1.5 mole of SO3 = 4.5
number of oxygen atom = 4.5 * 6.02 * 10^23 = 2.709 * 10^24

Option D:

moles of O in 3 mole of H2O = 3
number of oxygen atom = 3 * 6.02 * 10^23 = 1.806 * 10^24

Hence, the answer is B.

Uploaded files:
  • Capture.JPG

3) In the question we are told that an UNREACTIVE gas is produced. This eliminates the options A & B, as the gases produced in them (O2 & NO) are reactive. The second hint in the question is that ALL nitrogen is REDUCED; which means no compound in the equation should have nitrogen as a constituent (the oxidation state of Nitrogen should be zero on products side). This eliminates option D, and we are left with option C, which is the right answer.

Uploaded files:
  • Capture.JPG

4) CH3CH(OH)CH2CH3 will have the highest boiling point, because it's a secondary alcohol with H-Bonding between its molecules.

The boiling points for the given options are in this order:

D (H-Bonding) > C (Dipole-Dipole) > B (Van Der Waals) > A (Van Der Waals)

Therefore, the answer is D.

Uploaded files:
  • Capture.JPG

5) Use, PV=(m/Mr)RT

Make Mr the subject of the equation,

Mr = mRT/PV

Put the given values in to the above equation, and solve,

Mr = (0.321)(8.31)(2500)/(1.00*10^-4)(2.08*10^6)
Mr = 32.06 ~ this is the Mr for S.

Therefore the answer is A.

Uploaded files:
  • Capture.JPG

6) Option A: No change in bond angle.
Option B: Bond angle increases from 109.5 (in CH4) to 180 (in CO2)
Option C: No change in bond angle.
Option D: Bond angle decreases from 120 (in ethene) to 109.5 (in polyethene)

Hence, then answer is D.

Uploaded files:
  • Capture.JPG

7) This is a simple error-finding question. According to given data, ΔH is +ive, which represents that the given reaction is endothermic. This eliminates the option A, as it represents an exothermic reaction.

For B, the arrow for Ea is wrong. It should have been from the lower dotted line to the peak.

For C, everything is correct. (C is the answer)

For D, the direction of the arrow for Ea is wrong; it should have been pointed upwards.

Uploaded files:
  • Capture.JPG

8) SO2 --> SO3 (Oxidation; as oxygen is added or oxidation state of S increases from +4 to +6)

SO3 --> SO4-2 (Neither; the oxidation state of S remains the same)

SO4-2 --> H2S (Reduction; the oxidation state of S changes from +6 to -2)

H2S --> SO2 (Oxidation; oxidation state of S changes from -2 to +4)

So answer is C.

Uploaded files:
  • Capture.JPG