Rates of Reaction

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

Aim:
I want to investigate how temperature effects the rate of reaction.

Equipment: 

• A beaker, conical flask
• Measuring cylinder
• Stopwatch
• Black cross on paper
• Water bath,
• Thermometer
• 0.1mol/L sodium thiosulfate
• 2.0mol/L hydrochloric acid

Method:

1. Put the 'X' on the bench mat and put the conical flask on the paper.

1. Measure 50mL of sodium thiosulfate solution and put it in the beaker.

1. Record the temperature of the sodium thiosulfate

1. Measure 5mL of HCl and pour this into the conical flask.
2. Pour the sodium thiosulfate into the conical flask, start the stopwatch and swirl the flask. Time how long it takes for the cross to disappear when viewed from above 

1. Wash out the flask thoroughly.
2. Repeat the experiment, using a water bath to heat the sodium thiosulfate solution to 30degrees, 40degrees and 50degrees. Keep the volume of the acid the same each time. 

Results:

Temperature (degrees Celsius)	Time (secs)
17	26
31	17
40	9
49	3

Conclusion:
For a successful collision to occur reactant particles must collide with sufficient energy and the correct orientation. As you increase the temperature, you increase the kinetic energy of the particles, increasing the likelihood for a successful collision to occur, increasing the rate of the reaction.

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

Aim:
I want to investigate how concentration effects the rate of reaction.

Equipment:

A beaker, conical flask

Measuring cylinder

Stopwatch

Black cross on paper

Water bath,

Thermometer

0.1mol/L sodium thiosulfate

2.0mol/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 10mL of sodium thiosulfate solution and put it in the conical flask.
3. Measure 40mL of water and put it into the conical flask. Swirl the flask to mix the contents.
4. Measure 5mL of acid. Pour the acid into the flask, start the stopwatch, and swirl the flask. Time how long it takes for the cross to disappear.
5. Wash out the flask thoroughly. Repeat the experiment using the other volumes of sodium thiosulfate and water. Keep the volume of the acid the same each time: 

• 10mL of sodium thiosulfate and 40mL of water.
• 20mL of sodium thiosulfate and 30mL of water.
• 30mL of sodium thiosulfate and 20mL of water.
• 40mL of sodium thiosulfate and 10mL of water.
• 50mL of sodium thiosulfate and 0mL of water.

Results:

Volume of sodium thiosulfate (mL)	Volume of water (mL)	Time (secs)
10	40	335
20	30	125
30	20	77
40	10	49
50	0	36

Conclusion:
For a successful collision to occur reactant particles need to collide with sufficient energy and the correct orientation. As you increase the concentration you increase the number of reactant particles present, increasing the likelihood for a successful collision to occur, increasing the rate of the reaction.



Experiment 3:
Investigating the affect of Surface Area on Reaction Rates
Level 1 SciPad page 130

Aim:
I want to investigate how surface area affects the rate of a reaction.

Equipment:

• Boiling tube
• Calcium Carbonate chips and powder
• Hydrochloric acid
• Measuring cylinder
• Spatula

Method:

1. Measure 2mL of hydrochloric acid and put this in the boiling tube.
2. Holding your boiling tube over a sink or heat proof mat, add a pea-sized amount of calcium carbonate powder to your boiling tube. Record your observations.
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. Record your observations.

Results:

When i added the powder to the acid it fizzed vigorously but stopped reacting within a few seconds.
When i added the chips to the acid it created a few bubbles and continued to react for the following minute at the same slow rate.


Conclusion:
For a successful collision to occur reactant particles must collide with sufficient energy and the correct orientation  As you increase the surface area you increase the number of reactant particles able to react, increasing the likelihood for a successful collision to occur, increasing the rate of the reaction.

Experiment 4
Investigating the effect of a catalyst on a chemical reaction
Level 1 SciPad page 133

Aim:
I want to find out if a catalyst has an effect on the rate of a reaction.

Equipment:

• Three test tubes
• Test tube rack
• 10mL measuring cylinder
• dropping pipette
• granulated zinc
• copper turnings or powder
• dilute sulfuric acid

Method:

1. Add roughly the same mass of zinc to test tube 1 and 3.
2. Add roughly the same mass of copper to test tube 2 and 3.
3. Add 5mL of dilute sulfuric acid to test tube 1. Note the rate of gas bubbles produced.
4. Add 5,L of the acid to test tube 2. Note the rate of gas bubbles produced.
5. Add 5,L of the acid to test tube 3. Note the rate of gas bubbles produced.

Results:

Test tube number one which contained just the zinc and the acid bubbled and fizzed quite a bit and continued to do so for a minute or two.
Test tube number two which contained just the copper and the acid hardly did anything, with any a few bubbles forming, mainly on impact of the copper.
Test tube number 3 which contained the copper, zinc and acid bubbled and fizzed vigorously and continued to do so for around a minute.

Conclusion:
A successful collision is when two reactant particles collide with sufficient energy and with the correct orientation. In this experiment we looked at the inclusion of a catalyst which in this case was copper. We can tell it was copper because the catalyst itself never takes part in the reaction. It's job is to make it easier for the reactant particles to collide, which is why the copper and acid test tube had minimal activity. It is also why the rate zinc and acid reaction was increased in test tube three because there was the presence of the copper catalyst.