A 0.010 M solution has a volume of 1 L and contains 1.8 g of solute. What is the molar mass of the solute?
Answer and explanation
Correct answer: 180 g mol⁻¹
Molarity gives moles per litre of solution. Therefore, the moles of solute are n = M × V = 0.010 mol L⁻¹ × 1 L = 0.010 mol. The molar mass is then mass ÷ moles = 1.8 g ÷ 0.010 mol = 180 g mol⁻¹. Thus, option C is correct. The volume must be expressed in litres because the concentration is given in mol L⁻¹.
Frequently asked questions
What is the correct answer to this question?
180 g mol⁻¹
Why is this the correct answer?
Molarity gives moles per litre of solution. Therefore, the moles of solute are n = M × V = 0.010 mol L⁻¹ × 1 L = 0.010 mol. The molar mass is then mass ÷ moles = 1.8 g ÷ 0.010 mol = 180 g mol⁻¹. Thus, option C is correct. The volume must be expressed in litres because the concentration is given in mol L⁻¹.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Some Basic Concepts of Chemistry. Topic: Mole concept and molar mass.
