Question

How many grams of salt are needed to prepare 400 mL of a 10% brine solution?
A. 15 g salt
B. 25 g
C. 20 g of salt
D. 40 g of salt

Answer 1

Answer:

15 g salt

Explanation:

15g salt x 200mL sol'n = 30g salt 100 mL water So, you would put 30g of salt in a flask and add water up to 200ml.

Answer 2

Given:

volume 400 ml

10% brine solution

To get the mass you just need to multiply volume and the 10% (w/V).

• So convert 10% into fraction

• $\frac{10}{100} = 0.1$

So  $\frac{w}{V}=0.1$

given that the volume is 400 mL so

w = 0.1 × V

w = 0.1 × 400

w = 40 g of salt

Hence the 40 g of salt are needed to prepare prepare 400 mL of a 10% brine solution