Magnesium reacts with hydrochloric acid to produce hydrogen gas

CHEMISTRY · Multi-part · A Level · Chemistry · Kinetics · Kinetics

Problem

Magnesium reacts with hydrochloric acid to produce hydrogen gas. A series of experiments was carried out using a gas syringe to measure the volume of gas produced under different conditions. The first experiment used

0.10\,\text{g}

of magnesium ribbon reacting with

30\,\text{cm}^3

0.50\,\text{mol dm}^{-3}

HCl solution at

20^\circ\text{C}

. The results are:

Time / $\text{s}$	Volume of gas / $\text{cm}^3$
$0$	$0.0$
$15$	$18.6$
$30$	$32.3$
$45$	$44.3$
$60$	$54.8$
$75$	$62.7$
$90$	$68.4$
$105$	$72.6$
$120$	$74.9$
$135$	$75.4$
$150$	$75.6$
$165$	$75.6$
$180$	$75.6$

(1) Sketch a diagram of the apparatus used for this experiment. State the balanced equation for the reaction. (2) Draw a graph of this data and use your graph to calculate the initial rate

(\text{cm}^3\,\text{s}^{-1})

of reaction. (3) Interpret the shape of the graph and the variation in rate of reaction using collision theory. (4) Calculate the average rate of reaction over the first

150\,\text{s}

. (5) Explain why the volume of gas collected remains the same after

150\,\text{s}

. (6) This experiment was repeated using

0.05\,\text{g}

of magnesium ribbon. On the same axes as before, sketch the graph that would be obtained. Label this graph B. (7) The experiment was repeated under the same conditions but using

0.10\,\text{g}

of powdered magnesium. On the same axes, sketch the graph that would be obtained. Label this graph C. (8) The original experiment was repeated at

10^\circ\text{C}

. Again using the same axes, sketch the graph that would be obtained and label it graph D. (9) Sketch the Maxwell–Boltzmann distribution for the first experiment and the experiment at

10^\circ\text{C}

. Use this to explain the effect of changing the temperature on the rate of this reaction.

Related theory

Browse the problem library