Rates of reaction lab
Collect gas in a syringe and compare volume–time curves as you change concentration, particle size, temperature, mass and catalyst.
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Learning objectives
- describe the effect of concentration, pressure, particle size and temperature on the rates of reactions and explain these effects in terms of collisions between reacting particles
- interpret data obtained from experiments concerned with rate of reaction.
- define the term catalyst and describe the effect of catalysts (including enzymes) on the rates of reactions
- suggest a suitable method for investigating the effect of a given variable on the rate of a reaction
- show understanding that the half-life of a first-order reaction is independent of concentration
- Concentration–Time Graphs and Half-life
- Initial Rates Method
0.20 g of marble as small chips in 20 cm³ of 1.00 mol/dm³ hydrochloric acid at 25 °C. After 0 s the gas syringe reads 0 cm³.
- Volume of gas
- 0 cm³
- Rate at the tangent
- — cm³/s
- Half-life
- — s
Try this
0 of 4 doneDuring a run, drag the tangent back to the start of the curve to find the initial rate. (not done yet)
The rate is the gradient of the volume–time graph. It is greatest at the start, when the reactants are most concentrated, and falls to zero.
Use two different acid concentrations, with the marble used up both times. (not done yet)
More concentrated acid gives a steeper curve: acid particles hit the marble more often. The final volume is the same, because the same mass of marble reacts.
Compare large chips with powder of the same mass. (not done yet)
Powder has a much larger surface area, so many more acid particles collide with the marble each second.
Decompose H₂O₂ with no MnO₂, then with some MnO₂. (not done yet)
MnO₂ gives the reaction a pathway with a lower activation energy. It is a catalyst: the same mass of MnO₂ is left at the end.
Your readings
| # | t / s | V / cm³ | Remove |
|---|---|---|---|
| No readings yet. Set up a measurement, then record it. | |||