A20.0 ml sample of a nacl solution has a mass of 21.040 g. after the solution is evaporated to dryness, the dry salt residue has a mass of 4.348 g. calculate the following concentrations for the nacl solution.
a) mass/mass%
b) mass/volume%
c) molarity (m)

Mass NaCl = 4.348
Mass solution = 21.040 - 4.348 = 16.692
mass/mass % =
4.348/16.692
= 26%
mass/vol % =
21.7%
Molecular mass of NaCl = 58.5
Moles of NaCl = 0.074
Volume of solution = 0.02 L
Molarity = 3.7 mol/Liter

Evaporation: this is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas). water vapour droplets join together to make clouds! condensation: this is when water vapour in the air cools down and turns back into liquid water.

Forgot the question hahaha