Determine the number of grams of solute needed to make each of the following molal solutions.

a. 497g H2SO4.

b. 124g HNO3

Explanation:

Molality, m, is an unit of concentration defined as the moles of solute per kg of solvent.

a. The moles of solute, H2SO4 are:

1.16kg * (4.37mol / kg) = 5.07 moles H2SO4

Mass -Molar mass H2SO4: 98g/mol-

5.07 moles H2SO4 * (98g / mol) = 497g H2SO4

b. The moles of solute, HNO3 are:

1.97kg * (1.00mol / kg) = 1.97 moles HNO3

Mass -Molar mass HNO3: 63.01g/mol-

1.97 moles HNO3 * (63.01g / mol) = 124g HNO3

pure substance: iron,copper

impure substance: water,charcoal