Teachers' Professional License – Subject Test: Chemistry: free practice test

Past exam question Unit: History, Nature and Applications of Chemistry and Its Links to Other Sciences

1. Apublishing experts' personal opinions without scientific review

   Unreviewed personal opinions are not what peer-reviewed journals publish; publication involves scientific review.

2. Bpresenting general topics that non-specialists find easy to follow

   These journals target specialists and treat narrow topics, not general ones.

3. Ccovering the latest science news that people are discussing

   Relaying popular news is the job of general media; specialised journals publish original research.

4. Daccurate content that has been reviewed and checked by specialists ✓ Correct answer

   Specialised journals send papers to expert reviewers before publication, so the content is accurate and trustworthy.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.2 (scientific method, ethics and applications), indicator 5, p. 8

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Past exam question Unit: Laboratory Work and Basic Mathematical Skills

1. Athe internal pressure rises to the level needed for use

   Wrong: internal pressure is set by temperature and the gas's vapour pressure, not by the cylinder's position.

2. Bthe external pressure on the cylinder wall decreases slightly

   Wrong: the cylinder's position does not change the external pressure on its wall.

3. Cthe liquefied gas leaves the valve as a liquid jet

   Wrong: the gas should leave as vapour; liquid leaving the valve is hazardous and means the cylinder is tilted or inverted.

4. Dthe safety valve touches the gas phase, not the liquid ✓ Correct answer

   Correct: upright, the valve sits at the top above the liquid and contacts vapour, so it is not obstructed when it must vent pressure.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.3 (laboratory work and safety), indicator 4, p. 8

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Past exam question Unit: Matter, Its Properties and the Periodic Table

1. A[Ar] 3d³ 4s²

   This would mean two electrons removed from 3d; electrons are actually removed first from the higher-energy 4s.

2. B[Ar] 3d⁵ 4s²

   This is the configuration of the neutral manganese atom, not the ion.

3. C[Ar] 3d⁴ 4s¹

   This would mean one electron removed from each of 3d and 4s, which is incorrect.

4. D[Ar] 3d⁵ ✓ Correct answer

   The manganese atom is [Ar] 3d⁵ 4s²; forming Mn²⁺ removes the two 4s electrons and leaves [Ar] 3d⁵.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.6 (the periodic table and its properties), indicator 3, p. 9

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Past exam question Unit: Gas Laws, Stoichiometry, Solutions, Acids and Bases

1. AC₂H₄N₂

   C₂H₄N₂ has the correct ratio but is not the simplest one, because it can be divided by 2.

2. BCH₂N ✓ Correct answer

   Moles: C = 24 ÷ 12 = 2, H = 4 ÷ 1 = 4, N = 28 ÷ 14 = 2; the ratio 2 : 4 : 2 simplifies to 1 : 2 : 1, giving CH₂N.

3. CCHN

   CHN assumes equal moles of the three elements, but hydrogen has twice the moles of carbon.

4. DCH₄N

   CH₄N divides the moles of carbon and nitrogen by 2 but leaves the moles of hydrogen undivided.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.7 (chemical calculations, equations and gas laws), indicator 1, p. 9; n = m/M, then divide by the smallest

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Past exam question Unit: Gas Laws, Stoichiometry, Solutions, Acids and Bases

1. AOne solution was stirred more than the other

   Stirring only speeds up dissolving; it does not change how much solute the solvent can hold.

2. BThe volume of solution is smaller in one flask

   The solvent amounts are equal, so no volume difference explains the saturation.

3. CThe solute is volatile in only one of the flasks

   Volatility does not set the saturation state, and nothing suggests solute was lost.

4. DThe two solutions are at different temperatures ✓ Correct answer

   Solubility changes with temperature, so the same mixture can be saturated when cool and unsaturated when warmer.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.8 (solution chemistry), indicator 1, p. 10

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Past exam question Unit: Gas Laws, Stoichiometry, Solutions, Acids and Bases

1. AH₂PO₄⁻ + H₃O⁺ ⇌ H₃PO₄ + H₂O

   Here H₂PO₄⁻ accepts a proton from H₃O⁺, so it acts as a base, not an acid.

2. BH₃PO₄ + H₂O ⇌ H₂PO₄⁻ + H₃O⁺

   H₂PO₄⁻ is a product here, the conjugate base of H₃PO₄, and it donates no proton.

3. CH₂PO₄⁻ + H₂O ⇌ HPO₄²⁻ + H₃O⁺ ✓ Correct answer

   H₂PO₄⁻ donates a proton to water and becomes HPO₄²⁻, so it acts as a Brønsted-Lowry acid.

4. DHPO₄²⁻ + H₂O ⇌ H₂PO₄⁻ + OH⁻

   H₂PO₄⁻ is a product here, the conjugate acid of HPO₄²⁻, which accepted the proton from water.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.10 (acids and bases), indicator 2, p. 10

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Past exam question Unit: Kinetics, Thermochemistry, Electrochemistry and Equilibrium

1. AThe equilibrium shifts left and K decreases ✓ Correct answer

   Raising the temperature shifts the equilibrium toward the endothermic direction (left), and K decreases.

2. BThe amount of SO₃ at equilibrium increases because heat drives the reaction toward the products

   In an exothermic reaction heat acts as a product, so adding it favors the reverse reaction and SO₃ decreases.

3. CThe equilibrium shifts to the right, and both the amount of SO₃ and the value of K increase

   A shift to the right happens when the temperature is lowered, not raised, and K increases then.

4. DThe position of equilibrium does not change because the reaction is balanced and K stays constant

   Temperature is the one factor that changes K, so equilibrium does not stay unchanged when it varies.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.9 (kinetics, thermochemistry and chemical equilibrium), indicator 4, p. 10

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Past exam question Unit: Kinetics, Thermochemistry, Electrochemistry and Equilibrium

1. A+1

   This is chlorine's oxidation number in the hypochlorite ion (ClO⁻), not in perchlorate.

2. B+3

   This is chlorine's oxidation number in the chlorite ion (ClO₂⁻).

3. C+7 ✓ Correct answer

   Correct: x + 4(−2) = −1, so x = +7.

4. D+5

   This is chlorine's oxidation number in the chlorate ion (ClO₃⁻).

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.11 (electrochemistry), indicator 1, p. 10 ; sum of oxidation numbers = charge of the species

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Past exam question Unit: Hydrocarbons and Functional Groups in Organic Compounds

1. Asp³ ✓ Correct answer

   Sulfur has three oxygens and one lone pair, four domains in total, so the hybridization is sp³.

2. Bsp

   sp means only two electron domains (linear); sulfur has four.

3. Csp²

   sp² means three domains, but sulfur bonds to three oxygens and also has a lone pair.

4. Dsp³d

   sp³d needs five electron domains, which this ion does not have.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.12 (organic chemistry and hydrocarbons), indicator 3, p. 11

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Past exam question Unit: Hydrocarbons and Functional Groups in Organic Compounds

1. Apropanoic acid, CH₃CH₂COOH ✓ Correct answer

   A primary alcohol is oxidized first to an aldehyde (propanal) and then, with a strong oxidizing agent, on to a carboxylic acid.

2. Bpropanone, CH₃COCH₃

   Propanone is a ketone; it comes from oxidizing the secondary alcohol 2-propanol, not a primary alcohol.

3. Cmethyl propanoate, CH₃CH₂COOCH₃

   An ester does not form by oxidizing the alcohol alone; it forms when an alcohol reacts with a carboxylic acid.

4. Dpropene, CH₃CH=CH₂

   Propene forms when the alcohol loses water on heating with a concentrated acid; that is an elimination, not an oxidation.

Reference: ETEC Chemistry Teacher Standards (2020), Standard 6.7.13 (functional groups), indicator 5, p. 11

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