Rates Of Reaction

Experiment 1
Investigating the Effect of temperature on Reaction Rate
Level 1 SciPad page 126

Aim:
To investigate how temperature effects the rate of reaction.

Equipment: 
A Conical flask, beaker, measuring cylinder, stopwatch, black cross on paper, water bath, thermometer, 0.1 mol L sodium thiosulfate, 1.0 mol L, hydrochloric acid (HCl)

Method:
1. Put the 'X' paper on the bench mat, and put the conical flask on to of the paper.
2. Measure 50 mL of sodium thiosulfate solution and put it into the beaker.
3. record the temperature of the sodium thiosulfate
4. Measure 5 mL of HCl and pour this into the conical flask.
5. Pour the sodium thiosulfate into the conical flask, start the stopwatch and swirl the flask. Time how long it takes for the cross to dissapear when viewed from above (i.e. look down the mouth of the conical flask).
6. Wash out the flask thoroughly.
7. Repeat the experiment, using a water bath to heat the solution thiosulfate to 30 degrees then 40 degrees and finally 50 degrees. Keep the volume of acid the same each time.

Results:

Temperature (Degrees Celsius)	Time (seconds)
17	26.2
30	6
40	4.8
50	2.7

Conclusion:

For a reaction to occur the particles reacting have to be at the correct orientation and have an efficient amount of energy to react. When we took the first measurement with the temperature at 17 degrees it took a long time for the reaction to occur and the black cross to dissapear. when the Temperature was increased the time it took for the cross to dissapear decreased. This is because when we heated up the particles it caused them to move faster therefore creating more chances for the particles reacting resulting in a faster overall reaction.

Experiment 2
Investigating the Effect of Concentration on Reaction Rate
Level 1 SciPad page 128

Aim:
To investigate how concentration effects the rate of reaction.

Equipment:
A conical flask, measuring cylinder, stopwatch, black cross on paper, 0.2 mol L sodium thiosulfate, 1.0 mol L hydrochloric acid.

Method:
1. Put the 'X' paper on the bench mat, and put the conical flask on top of the paper.
2. Measure 10 mL of sodium thiosulfate solution and put it into the conical flask.
3. Measure 40 mL of water and put it into the conical flask. Swirl the flask to mix the contents.
4. Measure 5  mL of Hydrochloric acid. Pour the acid into the flask, start the stopwatch, and swirl the flask. Time how long it takes for the cross to dissapear.
5. Wash out the flask thoroughly. Repeat the experiment using the other volumes of sodium thiosulfate and water in the table below. Keep the volume of acid the same each time.

Volume of sodium thiosulfate (mL)	Volume of Water (mL)
10	40
20	30
30	20
40	10
50	0

Results:

Volume of sodium thiosulfate (mL)	Volume of Water (mL)	Time (seconds)
10	40	328
20	30	112
30	20	71
40	10	49
50	0	36

Conclusion:
For a reaction to occur the particles reacting must collide at the correct orientation and with an efficient amount of energy. When the volume of Sodium Thiosulfate was increased the Concentration of the solution increased also. When the concentration of a solution is increased there are more particles. With more particles there is more chance for the particles to collide and react with one another. This means the more Sodium thisulfate we added to the solution the less time it takes for the reaction to take place.

Experiment 3
Observing the Effects of Surface Area on Reaction Rate

Aim:
To observe how the surface area effects the rate of reaction.

Equipment:
Boiling tube, calcium carbonate chips and powder, hydrochloric acid, measuring cylinder, spatula.

Method:
1. Measure 2 mL of hydrochloric acid and pour this into your boiling tube.
2. Holding your boiling tube over a sink or heatproof mat, add a pea sized amount of calcium carbonate powder to your boiling tube.
3. Repeat the experiment, but this time use a chip of calcium carbonate that is roughly the same size as the spatula of powder you used previously.

Observations:
Powdered CaCo3: Fizzed violently for a very short time and dissolved quickly. It was a very fast reaction.
Chip CaCO3: Fizzed for a longer time and took a long time to dissolve. It was a slow reaction.

Conclusion:
For a reaction to take place the particles reacting must collide at the correct orientation with an efficient amount of energy. When we placed the powdered CaCO3 into the boiling tube it reacted very fast because the surface area was more spread out. But when we used a chip.