Best Answer: A molality of 2.55 indicates 2.55 mol of solute per 1 kg of solvent. Assume exactly 1 kg of water, and thus 2.55 mol of H2SO4.
The molar mass of H2SO4 is 2(1.0079 g/mol) (32.066 g/mol) 4(15.999 g/mol)=98.0778 g/mol.
2.55 mol H2SO4 x (98.0778g / 1 mol) = 2.50 x 10^2 g H2SO4
The mass of the water is 1 kg = 1000 g. the total mass of solution is
(2.50 x 10^2 g H2SO4) + (1000 g H2O) = 1.250 x 10^3 g solution
Use the mass and density of the solution to find the volume
1.250 x 10^3 g solution x (1 mL / 1.151g ) x (1 L / 1000mL) = 1.086 L solution
Finally, molarity is the number of moles of solute per liter of solution
(2.55 mol H2SO4 / 1.086 L solution ) = 2.35 M
Source(s):
Sapling Learning.com (the website we do our chemistry homework and that was the response given to me. good luck. hope you got it on time...
