Experimental Design of Rates of Reactions

TITLE: experimental design of rates of reactions
Aim
The aim of the experiments identifies the rates of reactions for variables with respect to change
in temperature and surface area.
Specific objectives
To identify the change on chemical reaction with change in temperature1
To identify the change on chemical reaction with change on surface area or size of an antacid
tablet
Prediction
The prediction of the first is experiment is that increase in temperature will lead to an increase on
the chemical reaction2. In the second experiment a reduced chemical reaction is predicted when
the surface area is increased3. This is simply because there is an increased area where the
chemical reaction is expected to take place as compared to a reduced surface area or size.
Materials
Part A
Thermometer (-10 °C to 110 °C)
400 cm3 beaker (for use as a water bath)
Plastic container with lid
2 glass tubes to hold 12-14 cm3 of liquid
0.05 mol dm–3 (or 40 g dm–3) sodium thiosulfate solution
1.0 mol dm–3 hydrochloric acid (or 0.5 mol dm-3 sulfuric acid)
Measuring cylinder
1 Nicolas. Vogel, Surface Patterning with Colloidal Monolayers. (Dordrecht: Springer, 2013). 78
2 Vijay K, Thakur, and Singha Amar S. Surface Modification of Biopolymers. (Hoboken, New Jersey: Wiley,
2015). 445
3 Dave J, Adams, Dyson, Paul J. and Tavener Stewart J.. Chemistry in Alternative Reaction Media. (Chichester,
West Sussex, England: J. Wiley, 2004). 56

Plastic graduated pipette
Stopwatch
Part B
Effervescent antacid tablets (at least four)
Sheet of paper
Spoon
Four clear 12-ounce (or larger) drinking glasses
Measuring cup
Teaspoon
Tap water
Stopwatch
Pen
Method
Part A
1. Using a measuring cylinder add 10.0 cm3 of 0.05 mol dm-3 of sodium thiosulfate solution
to the second tube. Measure the temperature of the sodium thiosulfate solution.
2. Write down the start temperature and add 1 cm3 of the acid to the thiosulfate solution and
start timing.
3. Record the reaction time by noting time taken form the cross to disappear from view.
4. Now record the temperature for the reaction mixture. Pour the cloudy contents of the vial
into the sodium carbonate solution (the ‘stop bath’).
5. Next add water from a very hot water tap to the plastic container. The water should be no
hotter than 55 oC. Note down the new temperature.
6. Now measure another 10.0 cm3 of 0.05 mol dm-3 sodium thiosulfate solution into a clean
tube.
7. Leave the reaction to take place in the hot bath for about 3 minutes.
8. Repeat steps 3 to 5 above.
9. Repeat the same procedure in order to obtain results for at least 5 different temperatures
in total.
Part B