Express concentrations of solutions quantitatively by preparing different concentrations of mixtures according to uses and availability of materials.

EXAMPLE: 1

What is the percent by volume concentration of a solution in which 70 ml of ethanol is diluted to a volume of 350 ml?

70 ml / 350ml x 100 = 20%

EXAMPLE: 2

What volume of acetic acid is present in a bottle containing 250 ml of a solution which measures 10% concentration?

X / 250 ml = 0.10

let x be the volume of acetic acid, 10% is 0.10 in decimal form (for ease of computing)

250 ml x 0.10 = 25 ml

therefor, 25 ml of acetic acid is present in 250 ml solution with 10% concentration

Example 3

Find the percent by mass in which 50 g of table salt (NaCl) is dissolved in 300 g of water.

50 g / 350 g x 100 = 14.2%

(note that 350 g is used in the substitution of formula instead of 300 g as stated in the given problem because implied in the formula that it must be mass of solution which is equivalent to mass of solute+mass of solvent)