Density & Moles

Density is a measurement of mass per volume
formula is -> d=m/v

examples
Water has a density of 1.0g/m. Mass of 11.5 mL of water? How many moles?
d=m/v  d * v = m  1.0 * 11.5 = 11.5g
11.5 * 1mol / 18 = 0.639mol of water


Unknown compound with molar mas of 65.0g/mol. If 0.25mol occupies a volume of 50mL, determine the compound density.
0.25mol * 65.0 / 1mol = 16.25g / 50mL = 0.33g/mol


The density of aluminum is 2.70g/mL. A solid piece of aluminum has a volume of 45.0mL. Find the number of atoms.
d = m/v   d*v = m  2.70 * 45.0 = 121.5g * 1mol / 27g * 6.02*10^23 / 1mol = 2.71*10^24


- JanCarlo Paysan