If 10 grams of NaOH is dissolved in 500 mL of solution, what is the molality of
Practice Questions
Q1
If 10 grams of NaOH is dissolved in 500 mL of solution, what is the molality of the solution? (Molar mass of NaOH = 40 g/mol)
0.5 m
1 m
2 m
0.25 m
Questions & Step-by-Step Solutions
If 10 grams of NaOH is dissolved in 500 mL of solution, what is the molality of the solution? (Molar mass of NaOH = 40 g/mol)
Step 1: Identify the mass of NaOH given in the problem, which is 10 grams.
Step 2: Find the molar mass of NaOH, which is given as 40 g/mol.
Step 3: Calculate the number of moles of NaOH using the formula: moles = mass (g) / molar mass (g/mol). So, moles of NaOH = 10 g / 40 g/mol = 0.25 moles.
Step 4: Identify the volume of the solution, which is 500 mL. Convert this volume to kilograms of solvent (water). Since 1 L of water is approximately 1 kg, 500 mL is 0.5 kg.
Step 5: Use the formula for molality (m), which is moles of solute / kg of solvent. Here, molality = 0.25 moles / 0.5 kg.
Step 6: Calculate the molality: 0.25 moles / 0.5 kg = 0.5 m.
Molarity vs. Molality – Understanding the difference between molarity (moles of solute per liter of solution) and molality (moles of solute per kilogram of solvent).
Calculating Moles – Calculating the number of moles from mass and molar mass.
Mass of Solvent – Recognizing that molality requires the mass of the solvent, not the total solution volume.
