What is the mass/volume percent of a solution with 75g of na2co3 dissolved in 20.0 g of water?
11%

9.3 %

30%

7.5%

percent by mass = 79%

Explanation:

Data Given:

mass of solute (Na₂CO₃) = 75 g

mass of solvent ( water ) = 20 g

mass percent of solution = ?

Solution:

Formula used to find percent by mass

                          mass of solute / mass of solution x 100 . . . . . . (1)

first we have to find mass of solution

              mass of solution = mass of solute + mass of Solvent . . . . (2)

put values in equation 2

             mass of solution = 75 g + 20 g

             mass of solution = 95 g

Now,

put values in equation 1

 Percent by mass = mass of solute / mass of solution x 100

 Percent by mass = 75 g / 95 g x 100

 Percent by mass = 79 %

so,

The percent of the solution by mass = 79%

***Note:

The same work can be used for the other values too i.e. if you have 20 g of solute and 75 g solvent.