Density
Introduction
Introduction • We can see the difference in density of different materials when we look at ... • wood floating on water • helium balloons floating in the air
Introduction • We can see the difference in density of different materials when we look at ... • iron sinking in water • lava lamps
Introduction
Properties
Properties • Density is an intensive property of matter. • The density of matter does not depend on the amount of matter. • Density does depend on the composition of the matter
m V D = Properties • Density is the mass of the matter divided by the volume of the matter. • The density of matter generally decreases as the temperature of the matter increases.
Properties • The density of some materials is given in this chart:
Properties
Doing the Math
m D m V D = V = Doing the Math • Density is the mass of the matter divided by the volume of the matter. • The volume of matter is the mass divided by the density. • The mass of matter is the density times the volume. m = D•V
Doing the Math
Examples
Examples • Example 1:
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm)
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3 m D = V
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3 m 340 g D = = V 750 cm3
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3 m 340 g D = = = 0.453333333 g/cm3 V 750 cm3
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3 m 340 g D = = = 0.453333333 g/cm3 = 0.45 g/cm3 V 750 cm3
Examples • Example 1: • A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block? V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3 m 340 g D = = = 0.453333333 g/cm3 = 0.45 g/cm3 V 750 cm3
Examples
Examples • Example 2:
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block? m D = V
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block? m m D = ➔ V = V D
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block? m m 37.4 g D = ➔ V = = V D 11.4 g/cm3
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block? m m 37.4 g D = ➔ V = = = 3.280701754 cm3 V D 11.4 g/cm3
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block? m m 37.4 g D = ➔ V = = = 3.280701754 cm3 V D 11.4 g/cm3 V = 3.28 cm3
Examples Example 2: A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block? m m 37.4 g D = ➔ V = = = 3.280701754 cm3 V D 11.4 g/cm3 V = 3.28 cm3
Examples
Examples • Example 3:
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm)
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3 m D = V
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3 m D = ➔ V
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3 m D = ➔ m = D•V V
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3 m D = ➔ m = D•V = (8.86 g/cm3)(0.157 cm3) V
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3 m D = ➔ m = D•V = (8.86 g/cm3)(0.157 cm3) V m = 1.39 g
Examples • Example 3: • What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l V = π•r2•l = π(0.0500 cm)2(20.0 cm) = 0.157 cm3 m D = ➔ m = D•V = (8.86 g/cm3)(0.157 cm3) V m = 1.39 g