Question

What is the mass of NaCl required to make 160 grams of a 12% solution of NaCl in water?

18 grams
19 grams
22 grams
24 grams

Answer 1

Second Option: 19 grams

Step-by-step explanation:

Total solution weight: 160 grams

percent of NaCl in the solution: 12%

You take these two numbers and multiply them with 12 being over 100:

160 *
`(12)/(100)` = 19.2 grams

and then just round to the nearest whole number: 19 grams

Answer 2

Answer: 19 grams

Step-by-step explanation:

percent by mass = (mass of part)/(mass of whole) * 100

this means that in this question, 12 = x/160 * 100, where x is the amount of NaCl.

this means 12/100 = x/160, and thus x = (160)(12/100)=19.2 grams

The closest option is B.