Question

What is the percent by mass of NaCl in a solution containing 3.6 g NaCl dissolved in water to make a 100.0 mL solution? (Hint: 1 mL of water = 1 g of water)

a.0.035%
b.3.5%
c.3.6%

Answer 1

The answer is c.3.6%.

If: 1 mL of water = 1 g of water
Then: 100 mL of water = 100 g of water

Now, 100 g of the solution is 100%. 3.6 g of NaCl is x.
100 g : 100% = 3.6 g : x

After crossing the products:
x = 100% * 3.6 g : 100 g
x = 3.6%