Aim:

To identify a substance as an acid before investigating the effect of temperature on the reaction rate and the gasses produced in reactions involving this acid.

Theory:

1. Blue litmus paper turns red in acid
2. The reaction of a chemical reaction increases speed as the temperature of the reactants increases
3. A sodium ion turns a Bunsen burner flame yellow
4. Shaking and mixing solution speeds up the process
5. Stirring it will speedup the process more
6. Acid + base = Salt + Water
7. Acid + Carbonate = Salt + Water + Carbon Dioxide (CO2)
8. Acid + Active metal = Salt + Hydrogen gas
9. CO2 turns colourless limewater milky
10. Hydrogen gas pops in a flame

Materials:

• Ice
• 100mL beaker
• Watch with a second hand / stop watch
• 50mL graduated cylinder
• 10mL graduated cylinder
• sheet of white paper
• thermometer
• 250mL beaker
• 2x 100mL conical flasks
• 3 test tubes
• 1 rubber stopped for test tube
• limewater
• Matches
• Bunsen burner
• Heat proof mat
• Test tube rack
• Delivery tube
• Blue litmus paper
• Hotplate
• Spatula
• Test tube holder

Method:

1. A piece of blue litmus paper was put in solution A and B and the colour was noted.
2. 50mL of solution A was measured in a graduate cylinder and poured into a conical flask.
3. Using a thermometer the temperature was taken and recorded on a result table.
4. A cross was marked on a sheet of paper and the flask was put on directly on top of the cross. A stopwatch was prepared.
5. 5mL Solution B was pour into the second measuring cylinder. The time was started immediately after solution B was poured into solution A.
6. The flask was swirled around a few times to mix the solutions making sure that the flask sat on the paper with the cross. The result of the time it took the cross to disappear was noted on the result table.
7. After this was done the glassware was washed out but this time the 50mL of Solution A in the flask was cool in an ice bucket until 10-15 degrees. The solution was quickly removed from the ice and Hydrochloric Acid was added. The result was recorded on the result table.
8. The experiment was repeated again but the 50mL Solution A was heated up to 40-60 degrees on a hotplate. The result again was recorded.

A small amount of substance C was put into a clean test tube. Hydrochloric acid was added to cover to substance. Immediately another test tube that was prepared was put over the one with the substance. After a minute the test tube on top was put over the Bunsen burner. Results were recorded.

Results:

Solution A: Sodium Thiosulphate

Solution B: Hydrochloric acid

Substance C: Hydrogen

Table 1: Time it takes for reaction takes place with different temperatures

Q We can be sure that Solution B is the acid because the blue litmus paper turned red when Hydrochloric acid was pour onto the paper.

Q The presence of Sodium was shown is Sodium Thiosulphate because the sodium turned yellow when sprayed over the Bunsen burner.

Q Sodium Thiosulphate and Hydrochloric acid reacts with each other. The Hydrochloric acid turns the Sodium Thiosulphate a milky colour so there is a possibility that Sodium Thiosulphate is limewater.