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Density. Mathematic Definition: D=m/v. Density is the amount of mass in a given volume. Volume. Particle Definition:. A measure of how tightly packed matter is . Liquid. Gas. Solid. Example of how to calculate density.
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Mathematic Definition: D=m/v • Density is the amount of mass in a given volume Volume
Particle Definition: • A measure of how tightly packed matter is Liquid Gas Solid
Example of how to calculate density • If you were given a rock with a mass of 243.5g and a volume of 94.3 cm3, what would be the rock's density? 243.5g 94.3 cm3 2.6 g/cm3 D= m/v
Your Turn • 500 grams of sugar occupies a volume of 315mL. What is the density of the sugar in g/mL? Round your answer to the nearest 100th. • Liquid A has a mass of 467 grams and a volume of 243ml. Liquid B has a mass of 27.2 grams and a volume of 12ml. Which liquid has a greater density? D=m/v D= 500g/315ml D=1.59g/ml Liquid A: D=m/v D= 467g/243ml D=1.92g/cm3 Liquid B: D=m/v D= 27.2g/12ml D=2.27g/cm3
If you know the density and the volume of a substance, you can solve for the mass. • Example: How many g of mercury would fill a 5 ml container if the density of mercury is 13.6 g/cm³? • Remember 1 ml = 1cm³ M= D x V M= 68g M= 13.6 g x 5 cm3 cm3
If you know the density and the mass of a substance, you can solve for the volume. • Example: How many ml of mercury would fill a 20g container if the density of mercury is 13.6 g/cm³? • Remember 1 ml = 1cm³ V= M/D V= 1.47ml V= 20g /13.6 g cm3
More Practice! Yay! • What is the mass of 45cm3 block of iron if the density of iron is 7.87 g/cm³? • The density of pure solid copper is 8.94g/cm3. What volume does 5,000g of copper occupy? M=d x V M= 7.87 g/cm3 x 45cm3 M=354.15g V= m/D v= 5,000g/ 8.94g/cm3 v=559.28cm3
Why do objects float/sink? FALSE!!! • Because they are “light” or heavy?” • If is more dense then the liquid it is in, it will sink!!! • if it is less dense than the liquid it is in, it will float!!!
Prove it! • Watch and be amazed! Predict what will happen.
Buoyancy • Floating objects are often called buoyant • It simply is relating the density of one object to another • Very simple, the more there is a difference between the density of an object and the density of the liquid it is floating in, the more buoyant that object.
Where would these blocks be located if the density of water is 1.0g/cm3? Density 0.5g/cm3 Density 1.0g/cm3 Density 0.9g/cm3 The difference between the water and the object it about half; that is why it is about half underwater. The difference between the water and the object is .1; that is why only a tenth of the block is sticking out of the water The density of the water and the object is the same; it can be placed anywhere in this liquid and it will stay. Think of a fish!