Hydrochloric Acid Investigation

PREDICTION

I predict that there must be an equal amount of hydrochloric acid and hydroxide for neutralisation to occur. If this happens sodium chloride will be produced to form a reaction that will be neutralised.

EQUIPMENT

50cm3 burettes

Conical flask

Sodium hydroxide (0.5m)

Hydrochloric acid (0.5m)

Universal indicator

Pipette droppers

25cm3 measuring cylinder

Thermometer

Safety goggles

PICTURE OF EQUIPMENT SET UP

PROCEDURE

. Collect all the necessary equipment and put it together ready for the experiment to begin.

2. Before you begin make sure everyone is wearing safety goggles and that no one is ready to mess around to ruin the experiment or cause any accidents.

3. Measure out 25ml of sodium hydroxide into a measuring cylinder.

4. Now pour the 25ml of sodium hydroxide into the conical flask.

5. Add 12 drops of universal indicator to the sodium hydroxide making sure the substance changes to a pH colour of 14.

6. Now wash the measuring cylinder thoroughly with water to clean it.

7. You can now pour 25ml of hydrochloric acid and pour it into the burette but make sure the tape is closed at the bottom before you do.

8. Make sure you have drawn out a table to collect your results that includes the colour of the solution the pH number, the temperature and the volume of acid in cm3 you have poured into the conical flask.

9. Open the tap of the burette and then close it when 1cm3 has poured out of the tap.

0. Now record the temperature of the liquid inside of the conical flask and check the pH then record it down into your table.

1. Repeat this step until there is no dramatic change in the pH or temperature, if this occurs increase the amount let out of the burette to 2cm3.

2. When you get to around a pH of 10, change the amount of hydrochloric acid let out to 0.2cm3.

3. Once you have reached to a pH of 7 your substance is neutralised and the experiment is over.

4. Clean and wash all the equipment used with water and pack it away.

FAIR TESTING

. Use the same volume of alkali and the same concentration.

2. Always have the same volume of universal indicator.

3. Always rinse through the apparatus thoroughly with water after each trial.

4. Initially add the acid in 2cm3 amounts, through to 1cm3 and then as we approach a weak alkali.

OBSERVATIONS

Results from experiment 1

Volume of acid cm3

pH number

Temperature oC

0

4

28

2

4

28

4

4

28

6

4

28

8

4

29

0

4

29

2

3

29

4

2

29

5

0

29

6

9

29

7

7

29

Results from experiment 2

Volume of acid cm3

Colour

pH number

temperature oC

2

blue green

4

29

4

blue green

4

29.5

6

blue green

3

30

8

blue green

3

30.25

0

blue green

3

30.5

2

blue green

3

30.75

4

Dark green

2

31

6

Dark green

2

31

7

Green

1

31.25

8

Green

1

31.25

9

Mid Green

0

31.5

9.5

Mid Green

0

31.5

20

Mid Green

9

31.5

20.5

Mid Green

9

31.5

20.9

Mid Green

9

31.5

21.3

Yellow

8

31.5

21.7

Mustard yellow

7

21.5

Results from experiment 3

Volume of acid cm3

Colour

pH number

Temperature oC

2

Blue green

4

29.5

4

Blue green

4

29.75

6

Blue green

3

30

8

Blue green

3

30.5

0

Dark green

2

30.5

2

Dark green

2

30.5

4

Mid green

1

31

6

Mid green

1

31

7

Green

0

31

8

Green

0

31

9

Green

0

31

21

Light green

9

31.5

21.5

Mustard yellow

7

31.5

CONCLUSION

From doing the following experiment I have found out that yes my prediction was correct as you can see from my results. In have found out that as the volume of acid is increased so is the temperature but as the volume of acid is increased the pH number decreases, this is because it is getting a weaker alkali as more acid is poured in.

EVALUATION

Overall my group's experiment went very successfully, we cleaned all the apparatus thoroughly, we used the same quantity of all the solutions and we added equal accurate amounts of the solutions to make sure that everything was very fair. We carried out the procedure safely without anybody getting hurt or messing around. People made accurate measurements and generally got on with the experiment quickly but thoroughly.

The only was I could improve the experiment for next time is to repeat more experiments.