Asolution 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? )

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%

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 = 2.11 g/mL

Volume of solution = 86.4 mL

Mass of Solute = 4.87 g

Mass of Solution = 183.2 g

w/w% of the solute =

w/w%=2.67%

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements