Answer to Question #160784 in Biochemistry for john doley

Question

How many grams of KCl (74.6 mw) would you weigh to make 200 ml of 4% (w/v) solution?

Answer 1

w/v solution means the weight/mass of solute dissolved in 100ml of solvent.

For calculating the percentage (%w/v) :

(Mass of solute÷ volume of solvent) × 100

So, 4% w/v solution means that 4g of KCl is dissolved in 100 ml of water.

To make a 200ml of 4% w/v solution, 8g of KCl is required to be dissolved in 200ml of solvent.

Proof:

%w/v= (mass of solute÷volume of solution)×100

Given: Mass of solute (KCl) = 8g

Volume of solvent=200ml

Now, put the value

(8÷200)×100= 4% ( the required percentage)

Hence, the answer is 8g. 8g of KCl is required to prepare 200ml of 4% w/v solution.