Question

A solution is made by dissolving 4.87 g of potassium nitrate in water to a final volume of 86.4 mL solution. What is the weight/weight % or percent by mass of the solute? (I got 5.64% but it said it was incorrect, and I can't figure it out?)

Answer 1

it's 5.63. I guess you don't round your answer.

Step-by-step explanation:

Answer 2

A solution is made by dissolving 4.87 g of potassium nitrate in water to a final volume of 86.4 mL solution. The weight/weight % or percent by mass of the solute is :

2.67%

Step-by-step explanation:

Note : Look at the density of potassium nitrate in water if given in the question.

You are calculating weight /Volume not weight/weight % or percent by mass of the solute

Here the weight/weight % or percent by mass of the solute is asked : So first convert the VOLUME OF SOLUTION into MASS

Density of potassium nitrate in water KNO3 = 2.11 g/mL

`density=(mass)/(volume)`

Density = 2.11 g/mL

Volume of solution = 86.4 mL

`2.11=(mass)/(86.4)`

`mass = 2.11* 86.4`

`mass=182.3grams`

Mass of Solute = 4.87 g

Mass of Solution = 183.2 g

w/w% of the solute =

`= (mass\ of\ solute)/(mass\ of\ solution)* 100`

`=(4.87)/(183.2)* 100`

w/w%=2.67%