rates of reaction Flashcards
Practical: Investigating surface area Affecting Rate 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.
Practical: Investigating concentration Affecting Rate of Reaction
Keep the mass of marble chips the same.
Use different concentrations of acid.
Measure volume of gas produced over time.
Practical: Investigating temperature Affecting Rate of Reaction
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).
Practical: Investigating use of a catalyst Affecting Rate of Reaction
Add hydrogen peroxide into a flask.
Add a small amount of MnO₂ powder.
Measure the volume of oxygen produced over time.
how does surface area affect ROR
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.
how does increasing gas pressure affect ROR
Increasing pressure means gas particles are squeezed closer together.
This increases the frequency of collisions between particles.
✅ Result: Rate of reaction increases.
how does increasing temperature affect ROR
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.
how does concentration increase affect ROR
Increasing concentration means more reactant particles in the same volume.
Particles are closer together, so collisions happen more frequently.
✅ Result: Rate of reaction increases.
how does a catalyst affect ROR
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.
what is a catalyst
s a substance that increases the rate of a reaction, but is
chemically unchanged at the end of the reaction
how does a catalyst work
by providing an alternative pathway with lower activation
energy
What do you measure in the practical investigating surface area and concentration?
Measure the volume of gas produced (e.g., CO₂) or time taken for a set volume of gas to be produced.
steps for Effect of Surface Area of Marble Chips
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.
What do you measure in the practical investigating catalysts on hydrogen peroxide?
Measure the volume of oxygen gas produced when hydrogen peroxide decomposes with a catalyst.
steps for effect of concentration of Hydrochloric Acid on the Rate of Reaction
Set up the equipment (flask, hydrogen peroxide, catalyst, gas syringe).
Step 1: Add a fixed volume of hydrogen peroxide (e.g., 50 cm³).
Step 2: Add a fixed mass of the solid catalyst (e.g., MnO₂, CuO, or KI).
Step 3: Start the reaction and measure the volume of oxygen gas produced at regular intervals (e.g., every 30 seconds).
Step 4: Repeat with different catalysts.
Step 5: Compare the volume of oxygen gas produced for each catalyst.
