Chemistry 9701 · AS & A Level · Atoms, molecules and stoichiometry

Atoms, molecules and stoichiometry — practice question

The equation $pV = nRT$ may be obtained from the laws of mechanics if gases are assumed to behave ideally.
(a(i))[1]

Add one line to the graph to represent the expected relationship for the same amount of an ideal gas.

(a(ii))[1]

State and explain, with reference to the graph, which of $T_1$, $T_2$ or $T_3$ is the lowest temperature.

(a(iii))[1]

Explain your answer to (ii) with reference to intermolecular forces.

(a(iv))[2]

State and explain the effect of pressure on the extent to which a gas deviates from ideal behaviour.

(b)[4]

A flask of volume $100\,\text{cm}^3$ was weighed once while it was filled with air and then again while it was filled with another gas, Y. The measurements, taken at $26^\circ\text{C}$ and $1.00 \times 10^5\,\text{Pa}$, are given below. Mass of flask containing air = $47.930\,\text{g}$. Mass of flask containing Y = $47.989\,\text{g}$. Density of air = $0.00118\,\text{g cm}^{-3}$. Calculate the relative molecular mass, $M_r$, of Y.

(c(i))[1]

Explain why nitrogen is so unreactive.

(c(ii))[1]

Explain why the conditions in a car engine lead to the production of oxides of nitrogen.

(c(iii))[1]

Give an equation for a reaction involved in the removal of nitrogen monoxide, $\text{NO}$, from a car’s exhaust gases, in the catalytic converter.

(c(iv))[1]

Write an equation for the formation of nitric acid from nitrogen dioxide, $\text{NO}_2$, in the atmosphere.

(c(v))[2]

Write equations showing the catalytic role of nitrogen monoxide, $\text{NO}$, in the oxidation of atmospheric sulfur dioxide, $\text{SO}_2$.

(iv)[1]

Write an equation for the formation of nitric acid from nitrogen dioxide, $\text{NO}_2$, in the atmosphere.

(v)[2]

Write equations showing the catalytic role of nitrogen monoxide, $\text{NO}$, in the oxidation of atmospheric sulfur dioxide, $\text{SO}_2$.

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