Calculating Density

Calculating Density PPT

1. NKCSD eChemistry Calculating Density

2. Common Chemistry Measurements Density (D) Density is a measure of the amount of mass in a given volume (D = m/V), measured in g/cm 3 or g/ mL. It is determined by first finding the mass and the volume of the object. Then, density is the mass of the object divided by its volume. 2

3. Density All substances have density. Liquids – The more dissolved solids in a solution, the denser the liquid. Cold water is more dense than warm water and will sink. Solids – Ice is less dense than water and will float. Various rocks, woods, and metals have a characteristic density specific to that substance. Gases – Cold air is more dense than warm air and will sink (the greater the kinetic energy, the greater the volume, and the less dense the gas). 3

4. Density Which diagram represents the liquid layers in the cylinder? K – Karo syrup (1.4 g/mL) V – vegetable oil (0.91 g/mL) W – water (1.0 g/mL) V V V K K K K W W W a) b) c) 4

5. Calculating Density When solving density problems, we will use the GUESS method! G U E S S GIVEN “What’s given in the problem” UNKNOWN “What we are looking for” EQUATION “Write the equation” SUBSTITUTION “plug numbers into the equation” SOLUTION “answer with correct label/units and round to the nearest 0.001” 5

6. Calculating Density Gasoline has a mass of 23.54 g and a volume of 124.3 mL. What is the gasoline’s density? G ivens U nknown E quation S ubstitution S olution m = 23.54 g v = 124.3 mL D D = m/v 23.54 124.3 0.189 g/mL 6

7. Calculating Density The density of aluminum is 2.7 g/ mL. What is the volume of 12.4 g? G ivens U nknown E quation S ubstitution S olution D = 2.7 g/mL m = 12.4 g v v = m/D 12.4 2.7 4.593 mL 7

8. Calculating Density The accepted density for copper is 8.96 g/ mL. Calculate the mass of a 25.0 mL sample of copper. G ivens U nknown E quation S ubstitution S olution D = 8.96 g/mL v = 25.0 mL m m = Dv 8.96 (25.0) 224 g 8

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