How do concentration of a reactant and temperature affect the rate of a chemical reaction

Outline the experiment

• Investigate the rate of reaction between magnesium and hydrochloric acid

• measure the volume of hydrogen gas produced

Effect of concentration on rate

• Fill a trough with water and invert a measuring cylinder full of water into it.

• Add a fixed length of magnesium ribbon to a conical flask.

• Add HCl of known concentration (e.g. 1.0 mol/dm³).

• Quickly seal with a bung and delivery tube connected to the measuring cylinder.

• Start a stopwatch and record volume of hydrogen gas every 10 seconds.

• Repeat with different concentrations (e.g. 0.5, 1.0, 1.5 mol/dm³).

Effect of temperature on rate

• Warm HCl to a set temperature using a water bath (e.g. 30°C).

• Fill a trough with water and invert a measuring cylinder full of water into it.

• Add a fixed length of magnesium ribbon to a conical flask.

• Add the heated HCl, seal quickly with bung and delivery tube.

• Measure volume of hydrogen gas every 10 seconds.

• Repeat at different temperatures (e.g. 30°C, 40°C, 50°C), keeping concentration constant.

What were the findings

• Higher concentration = more particles = faster rate of reaction (more collisions per second).

• Higher temperature = particles move faster = more frequent and energetic collisions → faster rate.

Plotting the graph

• x - axis: volume of gas

• y - axis: time