Various options are provided as possible answers to the following questions - NSC Physical Sciences - Question 1 - 2024 - Paper 2
Question 1
Various options are provided as possible answers to the following questions. Each question has only one correct answer. Choose the answer and write the letter (A–D) ... show full transcript
Worked Solution & Example Answer:Various options are provided as possible answers to the following questions - NSC Physical Sciences - Question 1 - 2024 - Paper 2
Step 1
1.1 The functional group for an ALDEHYDE is …
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Answer
The functional group for an aldehyde is the
carbonyl group. This group consists of a carbon atom double-bonded to an oxygen atom, which is characteristic of aldehydes.
Step 2
1.2 Which ONE of the following equations represents the reaction for the IDENTIFICATION of an UNSATURATED compound in the laboratory?
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Answer
The reaction for the identification of an unsaturated compound is represented by the equation:
A. CH3CH2CHCH2 + H2 → CH3CH2CH2CH3.
This equation shows a hydrogenation reaction, where an unsaturated compound reacts with hydrogen to form a saturated compound.
Step 3
1.3 Which ONE of the following is the EMPIRICAL formula of ethyl ethanoate?
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Answer
The empirical formula of ethyl ethanoate is:
A. C2H4O.
Empirical formulas represent the simplest whole number ratio of elements in the compound.
Step 4
1.4 In an experiment 5 g of calcium carbonate, CaCO3(s), reacts with EXCESS hydrochloric acid, HCl(aq), at a temperature of 40 °C. The volume of CO2(g) produced versus time is shown by CURVE P in the graph below. The experiment is repeated with 10 g of the same CaCO3(s) sample and an excess of HCl(aq) with the same concentration at 40 °C. Which ONE of the curves will now be obtained?
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Answer
When repeating the experiment with 10 g of CaCO3, we expect the volume of CO2(g) to increase. Therefore, the correct answer is:
B. Curve II.
Step 5
1.5 Which statement(s) is/are TRUE when a few drops of concentrated hydrochloric acid, HCl(conc), are added to the mixture?
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Answer
The addition of concentrated HCl will favour the reverse reaction, thereby decreasing the concentration of CrO2−4. The true statements are:
C. (i) and (iii) only.
Step 6
1.6 Consider the equation below for a hypothetical reaction. If the equilibrium constant Kc = 1 × 10−4, then …
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Answer
Given that Kc = 1 × 10−4, it indicates that the reaction favours the reactants. Therefore, we can conclude:
A. [A][B] > [C][D].
Step 7
1.7 Which ONE of the following shows the PRODUCTS for the reaction of oxalic acid with sodium hydroxide?
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Answer
The products for the reaction of oxalic acid with sodium hydroxide are:
A. (COO)2Na2(aq) + H2O(l) + CO2(g).
Step 8
1.8 Four solutions of different acids of the same concentration are compared. Which ONE of the following Ka values represents the WEAKEST acid at 25 °C?
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Answer
Among the given options, the weakest acid corresponds to the lowest Ka value:
A. 4.5 × 10−6.
Step 9
1.9 Which ONE of the following combinations is CORRECT for the changes occurring at the anode, cathode and in the electrolyte when the cell is in operation?
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Answer
In electrolysis, the changes observed at the anode and cathode are as follows:
B. Decreases | Increases | No change.
Step 10
1.10 Which ONE of the following redox reactions is SPONTANEOUS under standard conditions?
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Answer
The spontaneous redox reaction under standard conditions is:
