18 g glucose is dissolved in 500 g water. What is the molality of the solution?
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Answer and explanation
Correct answer: 0.2 mol kg⁻¹
Glucose has molar mass approximately 180 g mol⁻¹, so 18 g contains 18/180 = 0.10 mol. The solvent mass is 500 g = 0.500 kg. Molality = 0.10/0.500 = 0.20 mol kg⁻¹. It is important not to use the total solution mass or solution volume, because those belong to different concentration measures.
Frequently asked questions
What is the correct answer to this question?
0.2 mol kg⁻¹
Why is this the correct answer?
Glucose has molar mass approximately 180 g mol⁻¹, so 18 g contains 18/180 = 0.10 mol. The solvent mass is 500 g = 0.500 kg. Molality = 0.10/0.500 = 0.20 mol kg⁻¹. It is important not to use the total solution mass or solution volume, because those belong to different concentration measures.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Chapter 01: Solutions.
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