Percent Weight in Volume: % w/v

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Question 1 of 9

An undiluted antiseptic solution contains 0.175 % w/v Phenol BP. What is the volume of the solution that contains 700 mg of Phenol BP?

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700 mg of Phenol BP are contained in every 400ml of the solution.

EITHER

Convert the mass from milligrams to grams: 700 mg = 0.7 g

volume of the product = mass of solute x 100 ml
% w/v

Volume of antiseptic solution = 0.7 x 100 ml
0.175

Volume of antiseptic solution = 400 ml

0.175 % w/v means that there are
0.175 g Codeine Phosphate in 100 ml of antiseptic solution
Thus: 0.7 g Codeine Phosphate are in 0.7 x 100 ml of antiseptic solution
0.175
0.7 g Codeine Phosphate are in 400 ml of antiseptic solution

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Question 2 of 9

A person takes 5 ml of Magnesium Trisilicate Mixture BP 1988. If the concentration of Magnesium Trisilicate in the mixture is 5% w/v, how many milligrams of Magnesium Trisilicate did the person take?

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The person took 250 mg of Magnesium Trisilicate.

EITHER

mass of solute = % w/v x volume of product g
100

mass of Magnesium Trisilicate = 5 x 5 g
100

mass of Magnesium Trisilicate = 0.25 g = 250 mg

5 % w/v Magnesium Trisilicate means that:
100 ml of Mixture contains 5 g of Magnesium Trisilicate
Thus: 5 ml of Mixture contains 5 x 5 g of Magnesium Trisilicate
100
5 ml of Mixture contains 0.25 g ie 250 mg of Magnesium Trisilicate

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Question 3 of 9

A person washes a surface down with a solution made up using 0.3% w/v Chlorhexidine Gluconate solution. If the surface is now covered with 60 mg of Chlorhexidine Gluconate, how much Chlorhexidine Gluconate solution was added to the solution used to wash the surface?

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20 ml of Chlorhexidine Gluconate solution was used.

EITHER

Convert the mass from milligrams to grams: 60 mg = 0.06 g

volume of the product = mass of solute x 100 ml
% w/v

Volume of Chlorhexidine Gluconate solution = 0.06 x 100 ml
0.3

Volume of Chlorhexidine Gluconate solution = 20 ml

0.3 % w/v means that there are
0.3 g Chlorhexidine Gluconate (C G) in 100 ml of C G solution
Thus: 0.06 g Chlorhexidine Gluconate are in 0.06 x 100 ml of C G solution
0.3
0.06 g Chlorhexidine Gluconate are in 20 ml of C G solution

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Question 4 of 9

What is the % w/v concentration of a solution containing 1 mg of morphine sulphate in 1 ml of solution?

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% w/v

The concentration of morphine sulphate is 0.1 % w/v.

EITHER

Convert the mass from milligrams to grams: 1 mg = 0.001 g

% w/v = mass of solute x 100 (g/100ml)
volume of product

% w/v morphine sulphate = 0.001 x 100 (g/100 ml)
1

% w/v morphine sulphate = 0.1

1 ml of mixture contains 0.001 g of morphine sulphate
Thus: 100 ml contains 100 x 0.001 g = 0.1 g of morphine sulphate
1
Thus, concentration of solution is 0.1 g/ 100 ml = 0.1 % w/v

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Question 5 of 9

An athlete sprays 10 ml of a spray relief for muscular pains onto the muscles of the back. If the muscles are now covered with 480 mg of Glycol Monosalicylate - assuming that 100 % of the spray is on the muscles - what is the % w/v of Glycol Monosalicylate in the spray?

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% w/v

The concentration of Glycol Monosalicylate in the spray is 4.8 % w/v.

EITHER

Convert the mass from milligrams to grams: 480 mg = 0.48 g

% w/v = mass of solute x 100 (g/100ml)
volume of product

% w/v Glycol Monosalicylate = 0.48 x 100 (g/100 ml)
10

% w/v Glycol Monosalicylate = 4.8

10 ml of spray contains 0.48 g of Glycol Monosalicylate
Thus: 100 ml contains 100 x 0.48 g = 4.8 g of Glycol Monosalicylate
10
Thus, concentration of the spray is 4.8 g/ 100 ml = 4.8 % w/v

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Question 6 of 9

How many grams of Sodium Acid Phosphate BP are there in 500 g of Sodium Acid Phosphate BP Solution if the concentration of Sodium Acid Phosphate BP in the solution is 3.266 % w/v and the density of the solution is 1.008 g/ml? Answer to one decimal place.

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grams

There are 16.2 grams of Sodium Acid Phosphate BP.

You are given the concentration as % w/v ie as weight in VOLUME but the amount
of solution is given in grams. You need to first find out what VOLUME of solution
is involved - use the given density of the solution 1.008 g/ml, this tells you that:
1.008 g of solution has a volume of 1 ml

1.008 g of solution has a volume of 1 ml Thus:
500 g of solution has a volume of 500 x 1 ml 500 g of solution has a volume of 496.03 ml
1.008
Using the concentration, you can now find the mass of Sodium Acid Phosphate BP.
3.266 % w/v means that:
100 ml of solution contains 3.266 g of Sodium Acid Phosphate BP
496.03 ml of solution contains 496.03 x 3.266 g of Sodium Acid Phosphate
100
496.03 ml of solution contains 16.2 grams of Sodium Acid Phosphate BP.

You are given the concentration as % w/v ie as weight in VOLUME
but the amount of solution is given in grams. You need to first find
out what VOLUME of solution is involved - use the given density of
the solution 1.008 g/ml, this tells you that:

1.008 g of solution has a volume of 1 ml

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just type in an answer or click on the answer button.

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Question 7 of 9

Syrup BP has a density of 1.332 g/cm³ and its formula is:

Sugar 667 g
Purified Water up to 1000 g

What is the concentration of sucrose expressed as % w/v to one decimal place?

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% w/v

The concentration of sucrose is 88.8 % w/v.

You know that 1000 g of the syrup contains 667 g of sucrose. But the concentration needs to be expressed as grams per 100 cm³, therefore you need to change the amount of syrup from grams to a volume in cm³. You can do this using the density which is 1.332 g/cm³.

1.332 g of syrup has a volume of 1 cm³ therefore by ratios
1000 g of syrup has a volume of 1000 x 1 ie 750.75 cm³
1.332
Now you need the number of grams in 100 cm³ of syrup.

750.75 cm³ contains 667 grams of sucrose therefore by ratios:
100 cm³ contains 100 x 667 = 88.84 = 88.8 grams to one decimal place
750.75
Therefore the concentration is 88.8 g/100 cm³ = 88.8 % w/v

You know that 1000 g of the syrup contains 667 g of sucrose. But the
concentration needs to be expressed as grams per 100 cm³, therefore
you need to change the amount of syrup from grams to a volume in cm³.
You can do this using the density. The density is 1.332 g/cm³ Thus:

1.332 g of syrup has a volume of 1 cm³.

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answer or click on the Answer button to have a look at the answer.

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Question 8 of 9

Up to what volume - in litres - should Codeine Linctus BP 1988 be made if the Linctus is to contain 9 g of Codeine Phosphate, to give a concentration of 0.3% w/v Codeine Phosphate?

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litres

The Linctus needs to be made up to 3 litres.

EITHER

volume of the product = mass of solute x 100 ml
% w/v

Volume of Codeine Linctus = 9 x 100 ml
0.3

Volume of Codeine Linctus = 3000 ml = 3 litres

0.3 % w/v means that there are
0.3 g Codeine Phosphate in 100 ml of Linctus
Thus: 9 g Codeine Phosphate are in 9 x 100 ml of Linctus
0.3
9 g Codeine Phosphate are in 3000 ml = 3 litres of Linctus

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Question 9 of 9

How many kilograms of sucrose - to one decimal place - are there in 1.5 kg of Syrup BP if the concentration of the sucrose in the solution is 88.8% w/v and the density of the syrup is 1.332 g/ml?

Type in your answer and PRESS ENTER

There is 1.0 kg of sucrose in 1.5 kg of Syrup.

You are given the concentration as % w/v ie weight in VOLUME but the amount of syrup is in kilograms. You need to first find out the volume of the syrup involved. You can do this by using the density given for the syrup, 1.332 g/ml, which tells you that 1.332 g of syrup has a volume of 1 ml.

Convert the mass from kilograms to grams: 1.5 kg = 1500 g

From the density: 1.332 g of syrup has a volume of 1 ml Therefore by ratios,

1500 g of syrup has a volume of 1500 x 1 = 1126.13 ml
1.332

You now know the volume involved.
88.8 % w/v means that:
100 ml of syrup contains 88.8 g of sucrose. Therefore by ratios:
1126.13 ml of syrup contains 1126.13 x 88.8 g of sucrose
100
1126.13 ml of syrup contains 1000.00 g = 1.0 kg of sucrose.

You are given the concentration as % w/v ie weight in VOLUME but
the amount of syrup is in kilograms. You need to first find out the
volume of the syrup involved. You can do this by using the density
given for the syrup, 1.332 g/ml, which tells you that:

1.332 g of syrup has a volume of 1 ml

You do not need to clear the hint to continue; you can just type in
an answer or you can click on the Answer button to see the answer.

No, that is not the correct answer.

Have another go: just type in your new answer and press Enter.
If you continue to have problems, have a look at the answer.