Density Density

Density

• Density

• compares the mass of an object to its volume

• is the mass of a substance divided by its volume

• is defined as

Substances that have

• Substances that have

• higher densities contain particles that are closely packed together

• lower densities contain particles that are farther apart

• Metals such as gold and lead have higher densities because their atoms are packed closely together.

In the metric system, densities of solids, liquids, and gases are expressed with different units.

• In the metric system, densities of solids, liquids, and gases are expressed with different units.

• The density of a solid or liquid is usually given in

• grams per cubic centimeter (g/cm3)

• grams per milliliter (g/mL)

• The density of a gas is usually given in grams per liter (g/L).

Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3?

• Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3?

Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3?

• Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3?

• Step 1 Given 50.0 g; 2.22 cm3

• Need density, in g/cm3

• Step 2 Plan Write the density expression.

Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3? Step 3 Express mass in grams and volume in cm3.

• Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3? Step 3 Express mass in grams and volume in cm3.

• mass = 50.0 g volume = 2.22 cm3

• Step 4 Set up problem, calculate.

The oil pumped out of the ground is called crude oil, or petroleum. It is mostly made of hydrocarbons, or compounds that contain only carbon and hydrogen.

• The oil pumped out of the ground is called crude oil, or petroleum. It is mostly made of hydrocarbons, or compounds that contain only carbon and hydrogen.

• In April 2010, an oil rig in the Gulf of Mexico exploded, causing the largest oil spill in U.S. history.

• It leaked a maximum of 10 million liters a day into the Gulf of Mexico.

Because the density of this oil, 0.8 g/mL, was less than that of water, which is 1.00 g/mL, it floated on the surface, spreading a thin layer of oil over a very large surface.

• Because the density of this oil, 0.8 g/mL, was less than that of water, which is 1.00 g/mL, it floated on the surface, spreading a thin layer of oil over a very large surface.

The density of a solid is calculated from its mass and volume.

• The density of a solid is calculated from its mass and volume.

• When a solid is submerged, it displaces a volume of water equal to the volume of the solid.

In the figure below, the water level rises from 35.5 mL to 45.0 mL after the zinc object is added.

• In the figure below, the water level rises from 35.5 mL to 45.0 mL after the zinc object is added.

Scuba divers use lead weights to counteract their buoyancy in water. What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• Scuba divers use lead weights to counteract their buoyancy in water. What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• Step 1 Given 226 g lead

• 20.0 cm3 water displaced

• Need density (g/cm3) of lead

• Step 2 Plan. Write the density expression.

What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• Step 3 Express mass in grams and volume

• in cm3.

• mass of lead weight = 226 g

• volume of water displaced = 20.0 cm3

What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged?

• Step 4 Set up problem, calculate.

Density can be used as a conversion factor between a substance’s mass and volume.

• Density can be used as a conversion factor between a substance’s mass and volume.

If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• Step 1 Given 0.50 qt milk

• density of milk is 1.04 g/mL

• Need grams of milk

• Step 2 Write a plan.

If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• Step 3 Write equalities, conversion factors.

• 1 L = 1.057 qt 1 L = 1000 mL

• 1.04 g = 1 mL

If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt?

• Step 4 Set up problem, calculate.