Density Ratio of mass of object to its volume Density = Mass / volume = g / cm3
Example What is the density of 35.0 g of a substance with a volume of 25.0 cm3? D = m / v =35.0g / 25.0 cm3 =1.40 g / cm3
Practice What is the density of 2.75 kg of substance with volume of 250 cm3? D = M / V D= 2.75 kg / 250 cm3 = 2750 g / 250 cm3 = 11 g /cm3
Determine the volume of 35.2 g of CCl4 if the density is 1.60 g /cm3. D = M / V 1.60 g / cm3 = 35.2 g / V (1.60 g / cm3) V = 35.2 g V = 35.2 g / (1.60 g/ cm3) V = 22.0 cm3
How does density change as volume decreases? Density is an intensive property (Does not depend on amount of matter present.)
Specific Gravity Compares density of a substance with the density of a reference substance- usually water- usually both substances at same temperature
Specific gravity has NO units Measured with a hydrometer. Specific Gravity = Density of substance (g/cm3) Density of water (g/cm3) Units cancel out Specific gravity has NO units Measured with a hydrometer.
Hydrometers Used to measure: Strength of anti freeze in radiation Strength of acid in lead-acid battery