# Mass per unit volume of a substance

## Presentation on theme: "Mass per unit volume of a substance"— Presentation transcript:

Mass per unit volume of a substance
Density Mass per unit volume of a substance

Density: the amount of matter in a given space, or volume.
Density = Mass/Volume

Physical Properties Extensive physical properties depend on the amount (extent) of matter present Examples: length, volume and mass Intensive physical properties are intrinsic (fundamental) and do not depend on the amount of material present Examples: color, malleability, ductility, boiling point Can be used to identify a substance

Is density an extensive or intensive property?

Density May change at higher temperatures
Unit of density is grams/cubic centimeter or g/cm3 Unique so can be used to identify matter

Review Mass: the amount of matter in an object
Volume: the amount of space an object takes up Density = Mass Volume Remember: “Density will break your heart”

Density of a rectangular solid
Using the metric ruler, measure length, width and height of the object Find the mass of the solid. Use the formula: Volume = length x width x height Density = mass/volume

Displacement: density of an irregular object
Find the mass of the object. Place some water in the graduated cylinder and record the volume. Carefully add the object. Read the new volume. Subtract the old volume from the new volume. Density = mass/volume

Density of Liquids Immiscible: liquids that are insoluble in one another Density of water = 1 g/cm3 To determine: Find the mass of the empty graduated cylinder Find the mass of the graduate + liquid 2 - 1 = mass of liquid Read the volume of the liquid Density = mass/volume

Physical Properties, continued
Chapter 2 Section 2 Physical Properties Physical Properties, continued Using Density to Identify Substances Look at the table below to compare densities of several common substances.

Chapter 2 Section 2 Physical Properties

Physical Properties, continued
Chapter 2 Section 2 Physical Properties Physical Properties, continued Liquid Layers The graduated cylinder below contains six liquids. Each liquid is a different density so the liquids form layers. Density of Solids Knowing the density of a substance can also tell you what kind of substance it is.

Chapter 2 Standardized Test Preparation 1. What could you use to tell pyrite (fool’s gold) and gold apart? A volume B density C mass D state

Chapter 2 Standardized Test Preparation 1. What could you use to tell pyrite (fool’s gold) and gold apart? A volume B density C mass D state

Chapter 2 Standardized Test Preparation 2. What do you think would happen if you placed a nugget of pyrite into a beaker of mercury? F The pyrite would sink. G The pyrite would dissolve. H The mercury and the pyrite would react. I The pyrite would float.

Chapter 2 Standardized Test Preparation 2. What do you think would happen if you placed a nugget of pyrite into a beaker of mercury? F The pyrite would sink. G The pyrite would dissolve. H The mercury and the pyrite would react. I The pyrite would float.

Chapter 2 Standardized Test Preparation 3. If a nugget of pyrite and a nugget of gold each have a mass of 50 g, what can you conclude about the volume of each nugget? A The volume of pyrite is greater than the volume of gold. B The volume of pyrite is less than the volume of gold. C The volumes of the substances are equal. D There is not enough information to determine the answer.

Chapter 2 Standardized Test Preparation 3. If a nugget of pyrite and a nugget of gold each have a mass of 50 g, what can you conclude about the volume of each nugget? A The volume of pyrite is greater than the volume of gold. B The volume of pyrite is less than the volume of gold. C The volumes of the substances are equal. D There is not enough information to determine the answer.

Chapter 2 4. Which substance has the lowest density? F helium G pyrite
Standardized Test Preparation 4. Which substance has the lowest density? F helium G pyrite H mercury I gold

Chapter 2 4. Which substance has the lowest density? F helium G pyrite
Standardized Test Preparation 4. Which substance has the lowest density? F helium G pyrite H mercury I gold

Chapter 2 Standardized Test Preparation 1. Imagine that you have discovered a new element, and you want to find its density. It has a mass of 78.8 g and a volume of 8 cm3. To find the density of the element, you must divide the element’s mass by its volume. What is the density of the element? A g/cm3 B 0.98 g/cm3 C 9.85 g/cm3 D g/cm3

Chapter 2 Standardized Test Preparation 1. Imagine that you have discovered a new element, and you want to find its density. It has a mass of 78.8 g and a volume of 8 cm3. To find the density of the element, you must divide the element’s mass by its volume. What is the density of the element? A g/cm3 B 0.98 g/cm3 C 9.85 g/cm3 D g/cm3

Chapter 2 Standardized Test Preparation 2. Many soft drinks come in bottles that contain about 590 mL. If the density of a soft drink is 1.05 g/mL, what is the mass of the drink? F g G g H g I g

Chapter 2 Standardized Test Preparation 2. Many soft drinks come in bottles that contain about 590 mL. If the density of a soft drink is 1.05 g/mL, what is the mass of the drink? F g G g H g I g

Chapter 2 Standardized Test Preparation 3. If you have 150 g of pure gold and the density of gold is g/cm3 , what is the volume of your gold nugget? A cm3 B 7.76 cm3 C 0.98 cm3 D 0.13 cm3

Chapter 2 Standardized Test Preparation 3. If you have 150 g of pure gold and the density of gold is g/cm3 , what is the volume of your gold nugget? A cm3 B 7.76 cm3 C 0.98 cm3 D 0.13 cm3

Chapter 2 Standardized Test Preparation 4. Three objects have a mass of 16 g each. But their volumes differ. Object A, a liquid, has a volume of 1.2 mL. Object B, a solid, has a volume of 3.2 cm3. Object C, another solid, has a volume of 1.9 cm3. Which object is the least dense? F object A G object B H object C I There is not enough information to determine the answer.

Chapter 2 Standardized Test Preparation 4. Three objects have a mass of 16 g each. But their volumes differ. Object A, a liquid, has a volume of 1.2 mL. Object B, a solid, has a volume of 3.2 cm3. Object C, another solid, has a volume of 1.9 cm3. Which object is the least dense? F object A G object B H object C I There is not enough information to determine the answer.