Question

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%

Answer 1

The answer is 78.9%

Step-by-step explanation:

The percentage weight in volume indicates the mass of solute per volume. We will use the% weight/volume formula to calculate what the exercise asks for, as follows:
`%weight/volume=(solute weight)/(solution volume)x100%= (75 g)/(75+20)= 78.9%`

`percent Weight/volume=(solute weight)/(solution volume)x100=(75 g)/(75+20)x100=78.9`%

Answer 2

percent by mass = 79%

Step-by-step 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.