Speed of Reaction Flashcards
Explain speed of reaction in terms of concentration and collision theory
At higher concentration, there are more particles per unit volume, hence there is a higher frequency of effective collision the speed of reaction increases.
Explain speed of reaction in terms of temperature and collision theory
If the temperature is increased, the particles have more energy and move faster.
Hence there is a higher frequency of effective collisions and the speed of reaction increases.
Explain speed of reaction in terms of size of particles (s.a of particles - solid) and collision theory
When powdered reactants are used, the surface area exposed increased.
Hence, there is a higher frequency of effective collision and the speed of reaction increases.
Explain speed of reaction in terms of pressure (gases only) and collision theory
At higher pressure, the particles are closer together.
Hence there will be a higher frequency of effective collision and the speed of reaction increases.
Steeper gradient
Faster speed of reaction
Higher height
More products formed
Effect of particle size
Smaller pieces
Larger pieces
Effect of concentration
Higher conc.
Lower conc.
Effect of temperature
Higher temperature
Lower temperature
Graph for speed of reaction
volume of gas produced/cm^3 against time/s
How will vol. of gas produced be affected by solution if it is limiting agent?
Lesser conc. of limiting agent, lower vol. of gas and vice versa
Experiments to measure speed of rxn
Mass Loss Method
Mass of flask in g against time, Initial gradient gives initial speed of rxn. \
- cotton wool plug to stop spray loss
- reactants and gas going up in conical flask (eg hcl and marble chips losing co2 gas)
- one pan electronic balance
Gas syringe method
Vol. of gas against time, / fastest at start measuring initial rate of exn (cm^3/min)
- gas syringe
- gas going up in conical flask
- reactant
- stopwatch
Briefly describe how you
can carry out an experiment to
investigate the effect of surface area on speed of reaction.
1) Draw diagram.
2) React lumps of sandstone with acid and measure the volume of gas released per minute. Plot a graph.
3) Repeat using the same concentration and volume of acid.
4) However, using the same mass of powdered sandstone
5) Plot the results on the same graph and it should have a steeper gradient/more gas collected in a fixed time
What to include when describing experiment?
To describe an experiment, we usually include:
1) Diagram
2) Short description of the experiment. E.g. React with acid and collect the gas formed.
3) Factors to keep constant to ensure a fair experiment.
4) Factors to change.
5) Results
