Bulk Recipes
All solutions should be prepared using deionised or distilled water.
Dilute sodium hydroxide solution (0.1 M): Carefully add, in stages, 10 g
of sodium hydroxide with constant stirring to about 1 L of water. Continue
stirring until all of the solid has dissolved. Make the solution up
to 2.5 litre. Stopper, and mix thoroughly.
N.B. You will need to make up twice the quantity specified in this
recipe.
Dilute hydrochloric acid, approximately 0.1 M, may be prepared in the
fume hood by adding 22.5 cm3 of concentrated HCl to about 2 L of
deionised water and making it up to 2.5 L with deionised water. Stopper, and
mix thoroughly. It is stable
N.B. You will need to make up twice the quantity specified in this
recipe.
Dilute ammonia solution (approximately 0.1 M) is prepared as follows:
Using a fume cupboard, measure out 5.7 cm3 of 0.880 concentrated
ammonia solution (0.880 SG Ammonia is 35%) or 8 cm3 of 0.910
concentrated ammonia solution (0.910 SG Ammonia is 25%) in a graduated
cylinder. Add this to about 500 cm3 of deionised water in a beaker, and stir.
Pour the solution into a 1 litre graduated cylinder. Dilute to 1 litre with
water. Add to a labelled bottle and mix well.
N.B. You will need to make up twice the quantity specified in this
recipe.
Sodium chloride solution: One litre of approximately 0.1 M solution of
sodium chloride can be prepared by dissolving 5.85 g of NaCl in deionised
water to make 1 L of solution.
N.B. You will need to make up twice the quantity specified in this
recipe.
Dilute ethanoic acid solution (approximately 0.1 M): Dilute 5.8 cm3 of
glacial ethanoic acid to 1 L with water. Stopper, and mix thoroughly.
N.B. You will need to make up twice the quantity specified in this
recipe.
Lime water is prepared by adding about 200 g of calcium hydroxide to
2.5 L of water. Calcium hydroxide has a low solubility in water. Shake
vigorously at intervals over a period of time and finally allow to settle.
Decant off the clear limewater solution from above the undissolved solids.
Top up the vessel with deionised water and repeat the process.
Dilute hydrochloric acid, approximately 1.0 M, may be prepared in the
fume hood by adding 225 cm3 of concentrated HCl to about 2 l of deionised
water and making it up to 2.5 L with deionised water. Stopper, and mix
thoroughly. It is stable.
N.B. You will need to make up twice the quantity specified in this
recipe.
1 M sulfuric acid solution is prepared as follows:
(Always dilute sulfuric acid by adding the acid to water and not the other
way round.) 28 cm3 of the concentrated acid is added slowly to about 400
cm3 of deionised water containing about 20 ice cubes. The mixture is stirred
and made up to 500 cm3 in a volumetric flask with deionised water. The
flask is stoppered and inverted a number of times.
Iodine solution: An iodine solution that is approximately 0.05 M can be
produced by dissolving 20.0 g of potassium iodide in about 40 cm3 of
deionised water in a 1 litre volumetric flask with a glass stopper, and then
adding 12.7 g of iodine. When most of the iodine has dissolved, decant the
solution into another 1 litre volumetric flask, and dilute to 1 litre with
deionised water. If dilution is carried out before all the iodine has dissolved,
the remaining solid iodine can take a very long period to dissolve. The
iodine solution should be stored in small glass-stoppered bottles that are
stored in a dark place. Since iodine is volatile, the bottles should be kept
stoppered when not in use.
Copper(II) sulfate solution (approximately 0.2 M): Dissolve 50 g of
copper(II) sulfate pentahydrate (CuSO4.5H2O) in about 400 cm3 water and
make up to 1 L with water. Stopper, and mix thoroughly.
Dilute sodium hydroxide solution (2 M): Carefully add, in stages, 20 g of
sodium hydroxide with constant stirring to about 150 cm3 of water.
Continue stirring until all of the solid has dissolved. Make the solution up
to 250 cm3. Stopper, and mix thoroughly.
Starch solution: Pour with stirring a paste containing 5 g starch and a little
cold water into 250 cm3 of boiling water. Boil for two minutes, and allow to
cool. This solution should be made up freshly when required.
Amylase solution is made by dissolving 0.1 g of amylase in 100 cm3 of
water. This solution should be made up freshly when required.
Quantities of solutions required per class for the three years (based on a
class of 24, with twelve working groups of two)
Activity
Solution
Qty /
class /
course
OC 18-19, 36, 38
0.1 M HCl
5.0 L
OC 18-19 36, 38
0.1 M NaOH
5.0 L
OC 18-19
0.1 M CH3COOH
2.0 L
OC 18-19
0.1 M NH3
2.0 L
OC 18-19
0.1 M NaCl
2.0 L
OC 22, 28. OB 10-11
Lime water
2.5 L
OC27, 51, 52, 56
1.0 M HCl
5.0 L
OC 34
1.0 M H2SO4
0.5 L
OP 53, OB 3
0.2 M CuSO4
1.0 L
OB 3, OB 8, OB 49
Iodine solution
1.0 L
OB 3
2.0 M NaOH
0.25 L
OB 8
Starch solution
0.25 L
OB 8
Amylase solution
0.1 L