Question

10.0 cm3 of ammonia solution, NH3 with a density of 0.93 g/cm3 contains 0.45 g of NH3. What is the percentage by mass of this solution?

A) 4.5%

B) 4.8%

C) 5.0%

D) 5.2%

Answer 1

The percentage by mass of the ammonia solution is found to be approximately 4.84%, so the closest answer option is 4.8% (B).

Step-by-step explanation:

To calculate the percentage by mass of the ammonia solution, we use the mass of NH3 and the total mass of the solution. The mass of NH3 is given as 0.45 g, and the total mass of the solution is the volume times the density (10.0 cm3 x 0.93 g/cm3 = 9.3 g). The percentage by mass equation is (mass of solute / mass of solution) x 100%, which gives us (0.45 g / 9.3 g) x 100% = 4.84%. Hence, the closest answer to the given options is B) 4.8%%.