calculate the molality of a solution of 2.34g acetic acid, HC2H3O2, in 35.0 g water
molality= molesslolute/kgsolvent= 2.34/(molmass*.035)
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To calculate the molality of a solution, you need to know the mass of the solute and the mass of the solvent. In this case, the solute is acetic acid (HC2H3O2) and the solvent is water.
Step 1: Convert the mass of the solute (acetic acid) to moles.
To do this, you need to know the molar mass of acetic acid. The molar mass of HC2H3O2 is calculated as follows:
H: 1.01 g/mol (1 hydrogen atom)
C: 12.01 g/mol (2 carbon atoms)
O: 16.00 g/mol (2 oxygen atoms)
Total molar mass of HC2H3O2 = (2 x 12.01) + (4 x 1.01) + (2 x 16.00) = 60.05 g/mol
Now, divide the mass of acetic acid by its molar mass to calculate the number of moles:
2.34 g / 60.05 g/mol = 0.03896 moles
Step 2: Calculate the mass of the solvent (water) in kilograms.
The mass of water is given as 35.0 g. To convert this to kilograms, divide by 1000:
35.0 g / 1000 = 0.035 kg
Step 3: Calculate molality.
Molality (m) is defined as the number of moles of solute per kilogram of solvent. Divide the number of moles of acetic acid by the mass of water in kilograms:
m = 0.03896 moles / 0.035 kg = 1.113 mol/kg
Therefore, the molality of the solution is approximately 1.113 mol/kg.