At which temperature, in K, assuming constant pressure, is the volume of a fixed mass of gas at 127 °C doubled?

A.     200 K

B.     254 K

C.     400 K

D.     800 K

D

${\text{300 c}}{{\text{m}}^{\text{3}}}$ of water is added to a solution of ${\text{200 c}}{{\text{m}}^{\text{3}}}$ of ${\text{0.5 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ sodium chloride. What is the concentration of sodium chloride in the new solution?

A.     ${\text{0.05 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$

B.     ${\text{0.1 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$

C.     ${\text{0.2 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$

D.     ${\text{0.3 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$

C

One respondent stated that it would be best to start HLP1 with a mole type question and that these first three questions could have potentially tripped up candidates at the beginning of this paper. It must be emphasised that P1 covers all topics on the syllabus and, hence, any question can be asked as an Objective 1 or 2 multiple-choice type question based on any of the corresponding AS‟s on Topic 1 - Quantitative Chemistry. As regards the questions themselves, none of these three questions, in fact, posed a significant problem for candidates. 76% of candidates got Q1 correct, 68% Q2 and 78% Q3.

Four identical containers under the same conditions are filled with gases as shown below. Which container and contents will have the highest mass?

B

What is the pressure, in Pa, inside a 1.0 m³ cylinder containing 10 kg of H₂ (g) at 25 ºC?

R = 8.31 J K^–1 mol^–1; pV = nRT

A. $\frac{{1 \times {{10}^4} \times 8.31 \times 25}}{{1.0 \times {{10}^3}}}$

B. $\frac{{5 \times {{10}^2} \times 8.31 \times 298}}{{1.0}}$

C. $\frac{{1 \times 8.31 \times 25}}{{1.0 \times {{10}^3}}}$

D. $\frac{{5 \times {{10}^3} \times 8.31 \times 298}}{{1.0}}$

D

A compound with M_r = 102 contains 58.8 % carbon, 9.80 % hydrogen and 31 % oxygen by mass.
What is its molecular formula?

A_r: C = 12.0; H = 1.0; O = 16.0

A. C₂H₁₄O₄

B. C₃H₄O₄

C. C₅H₁₀O₂

D. C₆H₁₄O

C

Which solution neutralizes 50.0 cm³ of 0.120 mol dm^–3 NaOH (aq)?

A. 12.5 cm³ of 0.080 mol dm^–3 H₃PO₄

B. 25.0 cm³ of 0.120 mol dm^–3 CH₃COOH

C. 25.0 cm³ of 0.120 mol dm^–3 H₂SO₄

D. 50.0 cm³ of 0.060 mol dm^–3 HNO₃

C

What mass, in g, of hydrogen is formed when 3 mol of aluminium react with excess hydrochloric acid according to the following equation?

$${\text{2Al(s)}} + {\text{6HCl(aq)}} \to {\text{2AlC}}{{\text{l}}_{\text{3}}}{\text{(aq)}} + {\text{3}}{{\text{H}}_{\text{2}}}{\text{(g)}}$$

A.     3.0

B.     4.5

C.     6.0

D.     9.0

D

Which coefficients would balance this equation?

__ ${\text{Mn}}{{\text{O}}_2} +$ __ ${\text{HCl}} \to$ __ ${\text{MnC}}{{\text{l}}_2} +$ __ ${\text{C}}{{\text{l}}_2} +$ __ ${{\text{H}}_2}{\text{O}}$

C

In spite of a concern on the part of one teacher that this question was too difficult, this was one of the questions that students found easiest, with a Difficulty Index of 94%; hence it provided a nice easy start to settle students into the paper.

4.0 g of solid sodium hydroxide is added to ${\text{0.10 d}}{{\text{m}}^{\text{3}}}$ of ${\text{1.0 mol d}}{{\text{m}}^{ - 3}}$ aqueous sulfuric acid.
$${\text{2NaOH(s) + }}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{(aq) }} \to {\text{ N}}{{\text{a}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{(aq) + 2}}{{\text{H}}_{\text{2}}}{\text{O(l)}}$$
Which statement is correct?

A.     Neither reactant is in excess.

B.     0.10 mol ${\text{N}}{{\text{a}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}$ is formed.

C.     Excess ${{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}$ remains in solution.

D.     Excess NaOH remains in solution.

C

What are the coefficients of ${{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{(aq)}}$ and ${{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}{\text{(aq)}}$ when the following equation is balanced using the smallest possible whole numbers?

___ ${\text{C}}{{\text{a}}_3}{{\text{(P}}{{\text{O}}_4}{\text{)}}_2}{\text{(s)}} +$ ___ ${{\text{H}}_2}{\text{S}}{{\text{O}}_4}{\text{(aq)}} \to$ ___ ${\text{CaS}}{{\text{O}}_3}{\text{(s)}} +$ ___ ${{\text{H}}_3}{\text{P}}{{\text{O}}_4}{\text{(aq)}}$

D

What volume of carbon dioxide, in dm$^3$ under standard conditions, is formed when 7.00 g of ethene $({{\text{C}}_2}{{\text{H}}_4}{\text{, }}{M_{\text{r}}} = 28.1)$ undergoes complete combustion?

A.     $\frac{{22{\text{.}}4 \times 28{\text{.}}1}}{{7{\text{.}}00}}$

B.     $\frac{{22{\text{.}}4 \times 7{\text{.}}00}}{{28{\text{.}}1}}$

C.     $\frac{{2 \times 22{\text{.}}4 \times 28{\text{.}}1}}{{7{\text{.}}00}}$

D.     $\frac{{2 \times 22{\text{.}}4 \times 7{\text{.}}00}}{{28{\text{.}}1}}$

D

Under which conditions does ${\text{C}}{{\text{H}}_{\text{4}}}$ have the same number of molecules as ${\text{100 c}}{{\text{m}}^{\text{3}}}$ of ${{\text{O}}_{\text{2}}}$ at 27 °C and $1.0 \times {10^5}{\text{ Pa}}$?

D

Some teachers were worried about the use of a skeletal formula for the benzene ring. Certainly skeletal formulas are not on the syllabus but the benzene ring is.

7.102 g of Na₂SO₄ (M = 142.04 g mol^–1) is dissolved in water to prepare ${\text{0.5000 d}}{{\text{m}}^{\text{3}}}$ of solution. What is the concentration of ${\text{N}}{{\text{a}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}$ in ${\text{mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$?

A.     $2.500 \times {10^{ - 2}}$

B.     $1.000 \times {10^{ - 1}}$

C.     $1.000 \times 10$

D.     ${\text{1.000}} \times {\text{1}}{{\text{0}}^{\text{2}}}$

B

Which expression gives the sum of all the coefficients for the general equation for the complete

combustion of hydrocarbons?

___ ${{\text{C}}_x}{{\text{H}}_y}{\text{(g)}} +$ ___ ${{\text{O}}_{\text{2}}}{\text{(g)}} \to$ ___ ${\text{C}}{{\text{O}}_{\text{2}}}{\text{(g)}} +$ ___ ${{\text{H}}_{\text{2}}}{\text{O(l)}}$

A.     $1 + x + \frac{y}{4}$

B.     $1 + x + \frac{y}{2}$

C.     $1 + 2x + \frac{{3y}}{4}$

D.     $1 + 2x + \frac{{3y}}{2}$

C

Although this might have seemed unfamiliar, nearly 50% gave the correct answer. Many thought this was too challenging for an early question. The examination questions are, and have been for many years, presented in topic order. Those candidates who find the more mathematical manipulation testing should, perhaps, be advised the tackle the questions in a different order.

Which graph represents the relationship between volume and pressure for a fixed mass of gas at constant temperature?

D