The mole fraction of NaCl, in a solution containing 1 mole of NaCl in 1000g of water is:
Correct answer: A. 0.0177
- A. 0.0177
- B. 0.001
- C. 0.5
- D. 0.244
Explanation
Mole fraction of a component X in a solution is defined as the ratio of the number of moles of X to the total number of moles of all components in the solution.Mole fraction of NaCl = moles of NaCl / (moles of NaCl + moles of water)In this case, 1 mole of NaCl is dissolved in 1000 g of water. We can calculate the number of moles of water as follows:moles of water = mass of water / molar mass of water = 1000 g / 18.015 g/mol = 55.49 molSo, the total number of moles of all components in the solution is:moles of NaCl + moles of water = 1 mol + 55.49 mol = 56.49 molTherefore, the mole fraction of NaCl is:mole fraction of NaCl = moles of NaCl / (moles of NaCl + moles of water) = 1 mol / 56.49 mol = 0.0177 (rounded to four significant figures)Hence, the correct answer is A) 0.0177.
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The mole connects the microscopic number of particles with measurable mass, using Avogadro's number, 6.022 × 10²³ particles per mole. Questions involve molar mass, conversion between mass, moles and particles, percentage composition, empirical and molecular formulas, and distinguishing atoms, molecules, ions and formula units.
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