1. If you dissolve 600mg of glucose in 500ul of water, how much of this solution

Question

1. If you dissolve 600mg of glucose in 500ul of water, how much of this solution do you need to use to make 10ml of 22mg/ml glucose?

2. You want to make 35ml of a solution of potassium chloride in water at 450mg/ml. If you have 22ml of potassium chloride at 1.1g/ml in water, how would you make the desired solution?

3.you have 100ml each of 300mg/ml sodium phosphate, 350mg/ml sodium chloride, and 150mg/ml potassium nitrate. You want to make one liter of a solution containing 1.0mg/ml sodium phosphate,13mg/ml sodium chloride, and 15mg/ml potassium nitrate. How much of each starting solution do you need to use and how much water do you need to add?

4. You have 100ml each of 150mg/ml human chorionic gonadotropin, 25x HCG buffer, and 450mM potassium chloride. You want to make 1 liter of a solution that is 1.8mg/ml human chorionic gonadtropin, 1x HCG buffer, and 40.5mM potassium chloride. How much of each starting solution will you need to use and how much water do you need to add?

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Explanation / Answer

Ans 1)

Glucose concentration= 600mg/500µl (Stock Solution)

Solution needed= 10 ml of 22mg/ml of glucose.

Then we need 220mg of glucose/10ml (22mg/ml means 220mg/10ml)

When 600mg of glucose is present in 500µl

Then 220mg of glucose is present in = 220mgx500 µl /600mg= 183.4 µl

So take 183.4 µl of solution from the stock and add 9816.6 µl of water to it, it will give you 22mg/ml of glucose solution.

Ans 2)

Stock solution

22ml of potassium chloride at 1.1g/ml in water

22ml of potassium chloride at 1100 mg/ml in water (convert 1.1g into mg by multiplying 1.1gx1000=1100mg)

The amount of KCl present in 22ml of solution= 1100mg/mlx22ml=24200mg of KCl.

We need to prepare 35 ml of KCl in water at 450mg/ml.

Then we need 450mg/mlx35ml=15750mg of KCl

When 24200 mg of KCl is present in 22ml of water

Then 15750 mg of KCl is present in = 15750mgx22ml/24200ml= 14.3 ml

Now take 14.3 ml of solution from stock, add 20.7 ml of water to it, now you will get 35 ml of KCl in water at 450mg/ml.

Ans 3)

1.0mg/ml sodium phosphate, then in one liter solution will have= 1mg/mlx1000ml=1000mg

100ml of 300mg/ml sodium phosphate is there, so sodium phosphate present in 100ml=300mg/mlx100ml=30000mg (Stock solution).

Working solution:

We need 1000mg of sodium phosphate

When 30000mg of sodium phosphate present in 100ml means

1000mg of sodium phosphate present in 1000mgx100ml/30000mg=3.4 ml

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13mg/ml sodium chloride, then in one liter solution will have= 13mg/mlx1000ml=13000mg

100ml of 350mg/ml sodium chloride is there, so sodium chloride present in 100ml=350mg/mlx100ml=35000mg (Stock solution)

Working solution:

We need 13000mg of sodium chloride

When 35000mg of sodium chloride present in 100ml means

13000mg of sodium chloride present in 13000mgx100ml/35000=37.2 ml

15mg/ml potassium nitrate, then in one liter solution will have= 15mg/mlx1000ml=15000mg

100ml of 150mg/ml potassium nitrate is there, so potassium nitrate present in 100ml=150mg/mlx100ml=15000mg (Stock solution).

Working solution:

We need 15000 mg of potassium nitrate, so we need to take the complete stock solution.

3.4 ml of sodium phosphate

37.2 ml of sodium chloride

100ml of potassium nitrate (3.4ml+37.2ml+100ml=140.6) To this solutions add 859.4 ml of water, you will get the desired solution.

Ans 4)

1 liter solution should contain

1.8mg/ml human chorionic gonadtropin, then 1 liter will have 1.8mg/mlx1000ml=1800mg

We have 100ml of 150mg/ml of HCG so, 150mg/mlx100ml=15000 mg of HCG/100ml (Stock solution)

When 15000 mg HCG present in 100ml

Then 1800 mg HCG present in 1800 mgx100ml/15000mg= 12ml

So take 12 ml from the stock

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To prepare 1 liter of 1x HCG buffer from 25x HCG buffer= 25xbufferx( n mL/1000 mL)=1x buffer

Now calculate 25xn=1000

N=1000/24=4

So add 4 ml of 25x HCG buffer to the working solution

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To prepare 40.5mM potassium chloride

C1xV1=C2xV2  

C1-conc of the starting (stock solution)

V- Volume of starting (stock) solution needed to make the dilution (unknown)

C2- desired concentration of your final solution

V2- desired volume of your final solution.

450mMxV1=40.5mMx1000

V1=40.5mMx1000ml/450mM

=90 ml

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So take 12 ml of HCG from the stock, 4 ml of 25x HCG buffer, 90 ml of 40.5mM potassium chloride and then add 894 ml of water to get final desired concentration.

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