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Question 1 of 3
Strong Cetrimide Solution BP 1988 comes as a 40 % w/v solution. How many millilitres of this solution do you need to prepare 500 millilitres of 1 in 100 solution? Answer to 1 decimal place.
Type in your answer and PRESS ENTER.millilitres
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Express the concentration needed as a percent weight in volume.
1 in 100 means that 100 ml of solution contains 1 g of Cetrimide.
Thus the concentration needed is 1 g/100 ml ie 1 % w/v. -
Find the volume of Strong Cetrimide needed by using the equation:
Concentration1 x Quantity1 = Concentration2 x Quantity240 x Quantity1 = 1 x 500Quantity1 = 500 ml
40Quantity1 = 12.5 mlYou need 12.5 ml of the Strong Cetrimide Solution.Formula:
12.5 ml Strong Cetrimide Solution BP to 500 ml Water
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Question 2 of 3
Potassium Permanganate is supplied as a solution with concentration 1 in 1000. How many millilitres of this solution do you need to prepare 750 ml of a 0.0125 % solution of Potassium Permanganate? Answer to 2 decimal places.
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Express the concentration of the supplied solution as a percent weight in volume.
1 in 1000 means that 1000 ml of solution contains 1 g of Potassium Permanganate.
Thus 100 ml of solution contains 0.1 g of Potassium Permanganate.
Thus the concentration of the supplied solution is 0.1 g/100 ml ie 0.1 % w/v. -
Find the volume of 0.1 % Potassium Permanganate needed by using the equation:
Concentration1 x Quantity1 = Concentration2 x Quantity20.1 x Quantity1 = 0.0125 x 750Quantity1 = 9.375 ml
0.1Quantity1 = 93.75 mlYou need 93.5 ml of the stock solution of Potassium Permanganate.
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Question 3 of 3
You need to prepare 300 ml of a 10 % solution of Formalin. How much Formaldehyde Solution BP (34-38 %, density 1.08 g/ml) do you need?
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A 10 % solution of Formalin is the same as a 10 % v/v solution of Formaldehyde
Solution BP 1988. -
Find the volume of Formaldehyde Solution needed.
Concentration1 x Quantity1 = Concentration2 x Quantity2Since you are diluting Formaldeyde Solution BP itself, Concentration1 is 100 %.100 x Quantity1 = 10 x 300Quantity1 = 3000 ml
100Quantity1 = 30 mlFormula:
30 ml Formaldehyde Solution BP to 300 ml Water
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