The mass percent concentration of the solution is 13.9%. Option A
The total mass of the solution = mass of solute (sodium chloride) + mass of solvent (water)
Given:
Mass of sodium chloride (solute) = 25.0 g
Volume of water (solvent) = 155.0 mL
Density of water = 1.00 g/mL
First, convert the volume of water to its mass:
Mass of water = Volume of water × Density of water
Mass of water = 155.0 mL × 1.00 g/mL
Mass of water = 155.0 g
Total mass of the solution = Mass of sodium chloride + Mass of water
Total mass of the solution = 25.0 g + 155.0 g
Total mass of the solution = 180.0 g
Now, calculate the mass percent concentration of sodium chloride in the solution:
Mass percent concentration = (Mass of solute / Total mass of solution) × 100
Mass percent concentration = (25.0 g / 180.0 g) × 100
Mass percent concentration ≈ 13.9%