If 10 grams of NaCl is dissolved in enough water to make 500 mL of solution, what is the molality of the solution? (Molar mass of NaCl = 58.5 g/mol)
Practice Questions
1 question
Q1
If 10 grams of NaCl is dissolved in enough water to make 500 mL of solution, what is the molality of the solution? (Molar mass of NaCl = 58.5 g/mol)
0.34 m
0.17 m
0.85 m
0.50 m
Moles of NaCl = 10 g / 58.5 g/mol = 0.171 moles. Mass of solvent (water) = 0.5 kg. Molality (m) = moles of solute / kg of solvent = 0.171 moles / 0.5 kg = 0.34 m.
Questions & Step-by-step Solutions
1 item
Q
Q: If 10 grams of NaCl is dissolved in enough water to make 500 mL of solution, what is the molality of the solution? (Molar mass of NaCl = 58.5 g/mol)
Solution: Moles of NaCl = 10 g / 58.5 g/mol = 0.171 moles. Mass of solvent (water) = 0.5 kg. Molality (m) = moles of solute / kg of solvent = 0.171 moles / 0.5 kg = 0.34 m.
Steps: 7
Step 1: Identify the mass of NaCl given, which is 10 grams.
Step 2: Find the molar mass of NaCl, which is 58.5 g/mol.
Step 3: Calculate the number of moles of NaCl using the formula: moles = mass (g) / molar mass (g/mol). So, moles of NaCl = 10 g / 58.5 g/mol.
Step 4: Perform the calculation: 10 g / 58.5 g/mol = 0.171 moles of NaCl.
Step 5: Determine the volume of the solution, which is 500 mL. Convert this to kilograms of water (solvent). Since 1 L of water is approximately 1 kg, 500 mL = 0.5 kg.
Step 6: Use the formula for molality (m), which is moles of solute / kg of solvent. Here, m = 0.171 moles / 0.5 kg.
Step 7: Perform the calculation: 0.171 moles / 0.5 kg = 0.34 m.
