Question

Calculate the composition of each of the following solutions in mass/volume %.  

Be sure

to answer all parts.

(a)

44.8 g

ethanol in 5.00

×

10² mL solution

   %

(b)

44.8 g

ethanol in

1.00 L

solution

   %

How many grams of solute are needed to prepare each of the following solutions? Be sure to answer all parts.

(a)

6.04

×

10²

g of

0.900% (mass/mass)

NaCl

 

g

(b)

6.04

×

10²

g of

1.25% (mass/mass)

NaC₂H₃O₂ (sodium acetate)

 

g

Answer 1

1.

a)   Mass by Volume percentage =
(Mass of solute in grams/Volume of solution in mL) x 100

= (44.8/500)x100

= 8.96g/100 ml

b) by Volume percentage =
(Mass of solute in grams/Volume of solution in mL) x 100

= (44.8/1000)x100

=4.48g/100ml

2.

a)

If the mass of the solution is 6.04×10² g, and the percentage mass of the solute is 0.900%, then the mass of the solute is

(6.04×10²  )x(0.0090)=5.436 g solute

b)

  If the mass of the solution is 6.04×10² g, and the percentage mass of the solute is 1.250%, then the mass of the solute is

(6.04×10²  )x(0.0125)= 7.55 g solute