[Jaime7078]

the density of 2 m sulfuric acid solution is 1.12 kg per liter. what is the total molar concentration of the solution? what is the average molecular weight? what is the mass fraction of oxygen?

[Borek]

Please read the forum rules. You have to show your attempts at answering the question to receive help.

[Jaime7078]

molar concentration: 2M
average molecular weight:total mass = 1120g, mass of sulphuric acid = 2 mol × 98 g/mol = 196 g = 0.196 kg, Mass of water: 1.12 kg - 0.196 kg = 0.924 kg, Moles of water: 924 g / 18 g/mol = 51.33 mol, Total moles: 2 mol + 51.33 mol = 53.33 mol,Average molecular weight: 1120 g / 53.33 mol ≈ 21 g/mol.
mass fraction of oxygen: oxygen in water=821.33 g oxygen in h2s04=128 g, mass fraction = 84.7%

the thing is I dont if I should include water in my calculations because it doesn't specify that the solution is aqueous. I thinking I should have used that average molecular weight = density/concnetration or something

[Borek]

the thing is I dont if I should include water in my calculations because it doesn't specify that the solution is aqueous. I thinking I should have used that average molecular weight = density/concnetration or something

Good catch, but if nothing else is given, assuming water solution is reasonable, this is the most common case.

Besides, 1.12 kg/L for 2M fits water solution.