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Question 1 of 7
You have a saturated solution of Paracetamol in Ethanol (96%). The solubility of Paracetamol is 7 parts in Ethanol (96%). If the solution contains 420 ml of 96% Ethanol, how many grams of Paracetamol are there present?
grams
dissolves in 7 ml of 96 % Ethanol.
7 ml of 96% Ethanol contains 1 g of Paracetamol
7
420 ml of 96 % Ethanol contains 60 grams of Paracetamol.
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Question 2 of 7
You have a saturated solution of Alum (RMM 474.4) in Glycerol. Alum is soluble in 3 parts of Glycerol. Assuming the solubility to be correct, how many millimoles of Alum are dissolved in 600 ml of Glycerol? Answer to 4 significant figures.
- The solubility indicates that:
1 g of Alum dissolves in 3 ml of Glycerol
The solution is saturated and the solubility is assumed to be correct. Thus:
3 ml of Glycerol contains 1 g of Alum
Thus 600 ml of Glycerol contains 600 / 3 x 1 g ie 200 g of Alum. - Find the number of moles of Alum present:
Moles of Alum = Mass / RMM
Moles of Alum = 200 / 474.4 moles = 0.42158 moles = 421.58 millimoles
Millimoles of Alum = 421.6 mmoles to 4 sig figs
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Question 3 of 7
A saturated solution of Sucrose (RMM 342.0) contains 438.59 millimoles of Sucrose in 150 ml of water. What is the solubility of Sucrose in water? Answer to 1 decimal place.
- Find the mass of Sucrose dissolved in 150 ml of water.
Convert millimoles to moles: 438.59 mmoles = 0.43859 moles
Mass of Sucrose dissolved = Moles x RMM = 0.43859 x 342 g
Mass of Sucrose dissolved = 149.99778 g - Find in what volume of water 1 g of Sucrose is dissolved.
149.99778 g of Sucrose are dissolved in 150 ml of water.
Thus 1 g of Sucrose is dissolved in 1 / 149.99778 x 150 ml of water
Thus 1 g of Sucrose is dissolved in 1.00 ml of water
1 g of Sucrose is dissolved in 1.0 ml of water to 1 dec pl
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Question 4 of 7
- The solubility means that:
1 g of Urea dissolves in 1 ml of water
Since the solution is saturated and the solubility is assumed to be correct:
1 ml of water contains 1 g of Urea
Thus 225 ml of water contains 225/1 x 1 g = 225 g of Urea - Find the number of moles of Urea dissolved:
RMM Urea = 60.0
Moles of Urea = Mass / RMM = 225 / 60.0 = 3.75 moles
Moles of Urea = 3.750 moles to 4 sig figs
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Question 5 of 7
- Find the mass of Ammonium Chloride dissolved in 405 ml of water.
Mass of Ammonium Chloride = Moles x RMM
Mass of Ammonium Chloride = 2.8037 x 53.5 g = 149.99795 g - Find in what volume of water 1 g of Ammonium Chloride dissolves:
149.99795 g of Ammonium Chloride dissolves in 405 ml of water
Thus 1 g of Ammonium Chloride dissolves in 1/149.99795 x 405 ml of water
1 g of Ammonium Chloride dissolves in 2.70 ml of water
1 g of Ammonium Chloride dissolves in 2.7 ml of water to 1 dec pl
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Question 6 of 7
A saturated solution of Dimercaprol (a liquid) contains 450 ml of the solvent Arachis Oil. Dimercaprol is soluble in 18 parts of Arachis Oil. Assuming the solution has this solubility, how many millilitres of Dimercaprol are present?
1 ml of Dimercaprol dissolves in 18 ml of Arachis Oil.
Since the solution is saturated and the solubility is assumed to be as above:
Thus 450 ml of Arachis Oil contains 25 ml of Dimercaprol.
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Question 7 of 7
- The solubility indicates that 1 g of Hydrocortisone dissolves in 40 ml of 96 % Ethanol.
Since the solution is saturated and the solubility is assumed to be as above:
40 ml of 96 % Ethanol are associated with 1 g of Hydrocortisone. - Find out how much 40 ml of 96 % Ethanol weighs. Use the given density of 0.8038 g/ml
1 ml of 96 % Ethanol weighs 0.8038 g
Thus 40 ml of 96 % Ethanol weighs 40 x 0.8038 g = 32.152 g - Find out what MASS of Hydrocortisone is associated with 1000 g of Ethanol
32.152 g of Ethanol contains 1 g of Hydrocortisone
Thus 1000 g of Ethanol contains 1000/32.152 x 1 g = 31.102264 g of Hydrocortisone - Find out the number of moles of Hydrocortisone associated with 1000 g of Ethanol
Number of Moles = Mass/RMM
Number of Moles = 31.102264 / 362.5 = 0.0857993 moles = 85.799 millimoles
Number of Moles = 85.80 millimoles to 4 sig figs
- Find out how much 40 ml of 96 % Ethanol weighs. Use the given density of
0.8307 g/ ml:
1 ml of 96% Ethanol weighs 0.8307 g - Find out what mass of Hydrocortisone is associated with 1000 g of Ethanol.
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