A solution is prepared by dissolving 40 g of NaCl in 200 g of water. What is the mass per cent of NaCl in the solution? 

The Correct answer is 16.67%.

Key Points

• The formula for calculating mass percent of a solution is:
  Mass percent = (Mass of solute / Mass of solution) × 100
• In this case, the solute is NaCl (Sodium Chloride) and the solvent is water.
• The mass of NaCl is given as 40 g.
• The mass of water is given as 200 g.
• The mass of the solution is the sum of the mass of the solute and the solvent:
  Mass of solution = Mass of solute + Mass of solvent = 40 g + 200 g = 240 g
• Using the formula, the mass percent of NaCl in the solution is:
  Mass percent = (40 g / 240 g) × 100 = 0.1667 × 100 = 16.67%

 Additional Information

• Mass Percent
  • Mass percent, also called weight percent, is a way of expressing the concentration of a component in a mixture.
  • It is commonly used in chemistry to describe the concentration of a solute in a solution.
  • The formula for mass percent is:
    Mass percent = (Mass of component / Total mass of mixture) × 100
  • Mass percent is a dimensionless quantity and is expressed as a percentage.