Question

what is the molar mass of 2.50 g of an unknown sample dissolved in 130. ml of water with a concentration of 0.480 m

Answer 1

To find the molar mass of the unknown sample, we need to use the formula: Molar Mass = (Mass of Sample) / (Moles of Sample). The moles of the sample can be found using the formula for molality. Finally, we can find the molar mass of the sample by dividing the mass of the sample by the moles of the sample.

Molar mass = 40.1 g/mol

Step-by-step explanation:

To find the molar mass of the unknown sample, we need to use the formula:

Molar Mass = (Mass of Sample) / (Moles of Sample)

First, we need to find the moles of the sample. We can use the formula for molality to find this:

Molality = (Moles of Sample) / (Mass of Solvent in kg)

In this case, the mass of the solvent (water) is 130 g, which is equal to 0.13 kg. We can rearrange the formula to solve for moles:

Moles of Sample = Molality * Mass of Solvent

Using the given values, the moles of the sample is:

Moles of Sample = 0.480 mol/kg * 0.13 kg = 0.0624 mol

Finally, we can find the molar mass of the sample:

Molar Mass = (Mass of Sample) / (Moles of Sample)

Substituting the given values, the molar mass is:

Molar Mass = 2.50 g / 0.0624 mol = 40.1 g/mol

Answer 2

The molar mass of the unknown sample is found by calculating the number of moles from the molality and then dividing the sample's mass by the number of moles, resulting in approximately 40.06 g/mol.

Step-by-step explanation:

Finding the Molar Mass of an Unknown Sample

To find the molar mass of an unknown sample, one must first calculate the number of moles of the solute present in the solution. The molality (m) of a solution is calculated by dividing the moles of solute by the kilograms of solvent. Given the concentration of 0.480 m, we can calculate the moles of solute by multiplying the molality by the mass of the solvent in kilograms. In this case, 130 ml of water equals 0.130 kilograms.

Moles of solute = Molality × Mass of solvent (kg) = 0.480 m × 0.130 kg = 0.0624 mol.

To find the molar mass, we divide the mass of the sample by the number of moles:

Molar Mass = Mass of solute (g) ÷ Moles of solute = 2.50 g ÷ 0.0624 mol = 40.06 g/mol (approximately).