A solution is made by dissolving 37.5 g of sodium sulfide (Na2S) in

217 g of water.

What is the molality of the solution?

2.21m

Explanation:

Molality, m, is defined as the ratio between moles of solute (The substance that is in less amount, sodium sulfide) and kilograms of solvent (Water, in this case).

Thus, we need to convert mass of sodium sulfide to moles using its molar mass and grams of water to kilograms:

Moles Na2S (Molar mass: 78.0452g/mol):

37.5g * (1mol / 78.0452g) = 0.48 moles Na2S

Kilograms water:

217g * (1kg / 1000g) = 0.217kg

Molality:

0.48 moles Na2S / 0.217kg =

yes it is balanced

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole