rates of reaction

Put large marble chips in acid → measure gas produced every 30 seconds. Repeat with crushed marble chips (smaller pieces = bigger surface area). Compare how fast the gas is produced.

Keep the mass of marble chips the same. Use different concentrations of acid. Measure volume of gas produced over time.

Put sodium thiosulfate solution in a flask. Heat it to a certain temperature (use a water bath). Add HCl and start a timer. Time how long it takes for a black “X” under the flask to disappear. Repeat at different temperatures (e.g., 20°C, 40°C, 60°C).

Add hydrogen peroxide into a flask. Add a small amount of MnO₂ powder. Measure the volume of oxygen produced over time.

Breaking a solid into smaller pieces increases its surface area. More particles are exposed and available to react. This leads to more frequent collisions between reactant particles. ✅ Result: Rate of reaction increases.

Increasing pressure means gas particles are squeezed closer together. This increases the frequency of collisions between particles. ✅ Result: Rate of reaction increases.

Increasing temperature gives particles more energy. Particles move faster → collide more often and with more energy. More collisions have enough energy to overcome the activation energy. ✅ Result: Rate of reaction increases.

Increasing concentration means more reactant particles in the same volume. Particles are closer together, so collisions happen more frequently. ✅ Result: Rate of reaction increases.

A catalyst lowers the activation energy needed for a reaction. This means more collisions are successful (more particles have enough energy). ✅ Result: Rate of reaction increases.

s a substance that increases the rate of a reaction, but is chemically unchanged at the end of the reaction

by providing an alternative pathway with lower activation energy

Measure the volume of gas produced (e.g., CO₂) or time taken for a set volume of gas to be produced.

Set up the equipment (flask, acid, marble chips, gas syringe). Step 1: Change surface area of marble chips (use small pieces or powder, and larger chunks for comparison). Step 2: Change concentration of hydrochloric acid (e.g., 0.5 M, 1.0 M, 2.0 M). Step 3: Start the reaction and measure the volume of CO₂ produced at regular intervals (e.g., every 30 seconds). Step 4: Record the time taken for a fixed volume of gas (e.g., 50 cm³) to be produced.

Measure the volume of oxygen gas produced when hydrogen peroxide decomposes with a catalyst.

Measure a fixed volume (e.g. 50 cm³) of hydrochloric acid into a conical flask. Add a measured mass of marble chips (CaCO₃) and start the stopwatch. Record the volume of gas produced at regular time intervals using a gas syringe or water displacement. Repeat the experiment with different concentrations of hydrochloric acid.