Investigating the Solubility of Laundry bags

Aim: To investigate the solubility of 1 cm2 of Soluble Laundry bags in different pHs and temperatures.

Equipment

3 * thermometer

3 * 250 ml beaker

3 * 500 ml beaker

Tap Water

Hydrochloric acid

Sodium Chloride

45 * 1 cm squared pieces of Soluble Laundry bags

3 * Stirrers / spatulas

Ice (00C)

Room temperature water (200C)

400C water bath

600C water bath

Bunsen Burner

Gas

Universal Indicator

Stop clock

Prediction

From Previous work I know that most things dissolve in acid better than in lower pHs and that higher temperatures are also good for dissolving. So from this Preliminary work I predict that the shortest time to dissolve a 1 cm2 will be Hydrochloric acid at 1000C

Method

* Take 1 250 ml beaker and fill it with 100 ml of Hydrochloric acid.

* Take 1 500 ml beaker and fill it with roughly 250 ml of ice and measure and record the temperature somewhere.

* Place the 250 ml beaker with the 100 ml of Hydrochloric acid inside the 500 ml beaker of ice and drop a 1 cm2 piece of soluble laundry bag in the solution.

* As soon as the piece of bag is in the solution start a stop clock and stir the solution once every second

* When the bag is dissolved stop the stop clock unless the time reaches over 4 minutes and then you just leave it and record it as 4+.

* To record your results you need a chart like this:

30C

200C

400C

600C

1000C

pH 1 (HCl) 1st exp

pH 1 (HCl) 2nd exp

pH 1 (HCl) 3rd exp

* Fill in the gaps when you reach the relevant box

* To complete the other experiments you will need to wash up all the equipment you have used in the previous experiment.

* If you are repeating an experiment use the same equipment and solutions again and if you want to use different temperatures and pHs use the relevant one.

* Repeat the experiments again for all of the pHs and the different temperatures using the appropriate solutions and temperatures

* In all you should repeat each experiment three times

* For 1000C turn on a Bunsen burner and wait until it boils. When it is boiling do not remove the Bunsen because it will cool down just stir it while it is boiling

* For water and Sodium Hydroxide you will need result charts like these:

WATER

30C

200C

400C

600C

1000C

pH 7 (Water) Exp 1

pH 7 (Water) Exp 2

pH 7 (Water) Exp 3

HYDROCHLORIC ACID

30C

200C

400C

600C

1000C

pH 14 (NaOH) Exp 1

pH 14 (NaOH) Exp 2

pH 14 (NaOH) Exp 3

Fair Test

* To make it a fair test we should have had an automatic stirrer so that the solutions would be stirred exactly the same instead of an inexact hand stirrer.

* You should use exactly the right amount of each piece of equipment I have told you to use.

* You should also keep the temperatures exactly the same depending on what test you do e.g. 1000C should stay at 1000C for all three tests

* To make sure the ice was 00C we should have used crushed ice

Results

Hydrochloric Acid

30C

200C

400C

600C

1000C

pH 1 (HCl) Exp 1

4+

1.18

0.42

0.34

0.8

pH 1 (HCl) Exp 2

4+

1.19

0.46

0.33

0.8

pH 1 (HCl) Exp 3

4+

1.19

0.44

0.34

0.8

Water

30C

200C

400C

600C

1000C

pH 7 (H2O) Exp 1

4+

2.28

1.03

0.43

0.12

pH 7 (H2O) Exp 2

4+

2.28

1.04

0.42

0.11

pH 7 (H2O) Exp 3

4+

2.27

1.02

0.42

0.12

Sodium Hydroxide

30C

200C

400C

600C

1000C

pH 14 (NaOH) Exp 1

4+

4+

4+

4+

0.39

pH 14 (NaOH) Exp 2

4+

4+

4+

4+

0.38

pH 14 (NaOH) Exp 3

4+

4+

4+

4+

0.38

Conclusion

From my results I have found out that my prediction was correct. The more acidic the solution and the higher the temperature the faster the soluble bags dissolved in. From the Hydrochloric acid graph I notice that as the temperature increases the faster the bags dissolve at. From the Water graph you notice that as the temperature increases at first the speed of the solubility increases rapidly between 100C and 400C and then slowly increases as the temperature increases.

From the Sodium Hydroxide Graph you can straight away tell that Alkali is not the best solution for dissolving soluble laundry bags as only 1000C had an effect on dissolving it.

So from this experiment we have come to a Conclusion that the higher the temperature and the more acidic the solution is the faster the soluble laundry bags will dissolve in and the lower the temperature and the more alkali the solution the longer it takes for the soluble laundry bags to dissolve.