Chapter Introduction Lesson 1Physical Properties Lesson 2Density Lesson 3Solids, Liquids and Gases Lesson 4Chemical Properties Lesson 5Physical and Chemical Changes Lesson 6Chemical Reactions Chapter Wrap-Up
Physical Properties • Essential Question • How can we measure and describe the physical properties of matter?
Physical Properties • Matter • Atom • Physical property • Mass • Weight • Volume
What is matter? • Matteris anything that has mass and takes up space. • Ex. Air, glass, water, cup. • All have mass, all take up space. • Non Ex. Light, heat, emotions, thoughts • All do not have mass and do not take up space.
What is matter? (cont.) • The makeup of matter was a mystery to people for centuries until an ancient Greek philosopher Democritus first theorized about the atom. • Atomis a small particle of an element that still has the same chemical properties of the element.
What is matter? (cont.) • Atoms are tiny. Millions of atoms can fit in a space as small as this letter….i. • Atoms can combine with other atoms to make molecules. • Ex. Water
What are Physical Properties? • Physical properties a property that can be observed without changing the identity of substance. • Ex. Color, odor
What are Physical Properties? (cont.) • All matter has physical properties. These properties help us tell substances apart. • Mass is the amount of matter in an object. • Measured in grams or kilograms (g or kg) with a balance.
What are physical properties? (cont.) • Weightis the measurement of the pull of gravity on an object. • Measured in newtons (N) with a spring scale. • Weight depends on gravity, which can change depending on where the object is located. Ex.
What are physical properties? (cont.) • Volumeis the amount of space matter takes up. • Measured in millimeters (mL) using a graduated cylinder and in cm3 for solids. • 1 cubic centimeter (cm3) is equal to 1 millimeter (mL).
What are physical properties? (cont.) • Volume(cont.) • To measure the volume of a regularly shaped solid, like a book, you measure the length, width and height and multiply them all together. • Ex. length x width x height • To measure the volume of an irregularly shaped object, you measure the amount of water that is moved out of the way or displaced when the object is put in water. • Ex. Volume of water and object – volume of water alone
What are other physical properties? • Conductivity is the ability of a material to transfer heat and electricity. • Malleability is the ability to be bent, flattened or hammered without breaking. • Ductility is the ability to be pulled into thin wires without breaking. • Hardness is the ability of the material to scratch another material.
1. Which is not a physical property used to identify substances? A. hardness B. odor C. color D. beauty
2. What is the amount of space a sample of matter occupies? A. mass B. volume C. weight D. density
3. Which tool would be used to measure the mass of an object? A. spring scale B. graduated cylinder C. balance D. beaker
Density • Essential Question • What is density and how is it measured? • GLE PS 2: Calculate the density of large and small quantities of a variety of substances (e.g., aluminum foil, water, copper, clay, rock)
Density • Density • Fluid
What is density? • Densityis the measurement of how much mass fits within a certain volume. • Ex. Tennis ball and baseball (same size). Tennis ball floats in water while the baseball sinks in water. The tennis ball is less dense than the water and the baseball. The baseball is more dense (has more matter packed into the same volume of space) than the tennis ball and water. • Measured in grams per cubic centimeter. (g/cm3)
What is density? (cont.) • Calculate the density of an object by dividing its mass by its volume. Density (D) = mass (m) volume (v) • Ex. Volume = 73mL mass = 80.3g 80.3 ÷ 73 = 1.1g/mL or g/cm3
What does density depend on? • The density of a material depends on the masses of the particles that make up the material. • The density of a material also depends on the distance between the particles in the material.
What does density depend on? (cont.) • Density is constant for a given substance, regardless of the size of the sample. • Ex. A chocolate bar has a density of 1.2g/cm3. You break the bar into three different pieces. Every piece will have a density of 1.2g/cm3. • Because density is unique for each substance, it can be used to help identify materials.
Liquids and gases are fluids. • Fluidis a material that can flow and has no definite shape.
4. A student knows the mass of an object. What other variable does the student need to know to calculate the object’s density? A. color B. weight C. volume D. length
5. What is the formula for density? A. m x v B. v/m C. m/v D. v - m
6. Which would be most useful for identifying an unknown liquid? A. density B. volume C. mass D. weight
7. What is density measured in? A. grams per cubic centimeters B. grams per milliliters C. pounds per milliliters D. Both A & B
8. Which of the following is not true? A. Density is a measurement of how much mass fits within a certain volume B. Density is a physical property C. The density of water is 1.0 g/mL D. Density of an object changes when the mass changes.
Solids, Liquids and Gases • Essential Question • How does energy affect the properties of matter?
Solids, Liquids and Gases • Melting point • Freezing point • Boiling point • Solid • Liquid • Gas • Temperature
What are states of matter? • A state of matter is a form that matter can take. • On Earth, there are three common states of matter: solid, liquid and gas. • Scientists recognize another state of matter known as plasma. • Plasma is found in stars, lightning and neon lights.
What are states of matter? (cont.) • All matter is made of tiny particles that are constantly moving. • A solid is matter that has a definite shape and occupies a definite amount of space. - particles vibrate back and forth but do not move past one another. They “wiggle” in relatively fixed positions.
What are states of matter? (cont.) • A liquidis matter that takes up a definite amount of space but has no definite shape. • In liquids, the distance between particles is greater than in solids and they can slide past one another.
What are states of matter? (cont.) • A gasis matter that has no definite shape and does not take up a definite amount of space. • In a gas, particles move freely rather than staying close together.
How does heat affect the state of matter? • Recall that particles of matter are in constant motion. • Their motion depends on the energy they possess.
How does heat affect the state of matter?(cont.) Moving objects possess a type of energy called kinetic energy. • Particles with more kinetic energy move faster and farther apart. • Particles with less kinetic energy move more slowly and stay close together.
How does heat affect the state of matter? (cont.) • Not all the particles in a sample of matter have the same energy. • Temperature is a measure of the average kinetic energy of the particles in a material. • Matter can change from one state to another when energy is absorbed or released.
How does heat affect the state of matter? • When a substance changes from a solid to a liquid (melting) to a gas (vaporizing) – energy is being absorbed. • When a substance changes from gas to a liquid (condensing) to a solid (freezing) – energy is being released.
How does heat affect the state of matter?(cont.) • The state of matter can change in other ways. Sublimation occurs when a substance changes directly from a solid to a gas without going through a liquid state. • Ex. Dry ice – is solid carbon dioxide and at room temperature does not exist as a liquid but becomes a gas.
When does matter change states? • A solid that is a pure substance has a characteristic (unique) melting point. • Melting pointthe temperature at which the solid melts to become a liquid. • Ex. Sugar melting point = 186°C Salt melting point = 801°C • Because the substances melt at different temperatures, knowing the temperatures at which they melt will help you identify which substance is table salt and which is sugar.
When does matter change states?(cont.) • As a substance is heated, it absorbs energy and its temperature rises. • When the temperature reaches the melting point, the temperature stops increasing. • At this point, the solid is changing into a liquid and all the energy is spent breaking particles apart from one another. • After the substance has changed into a liquid, adding energy (heat) causes the temperature to increase again.
When does matter change states?(cont.) • The process of melting a solid can be reversed. • As the liquid cools, it loses energy and its particles lose kinetic energy and slow down. They become closer together. • The temperature of the material decreases until the freezing point is reached. • Freezing pointthe temperature at which a liquid changes into a solid. • During freezing, the temperature of the substance remains constant while the particles in the liquid form a solid. • After all the liquid has become a solid, the temperature begins to decrease again.
When does matter change states?(cont.) • Melting and freezing are opposite processes. • The freezing point of the liquid state of a substance is the same temperature as the melting point of the solid state. • Ex. Solid water melts at 0°C and liquid water freezes at 0°C
What is boiling point? • Remember that the change from a liquid to a gas is called vaporization. • Vaporization can occur within a liquid and at the surface of a liquid. • Vaporization that takes place at the surface of a liquid is called evaporation, which occurs at temperatures below the boiling point. • Ex. Puddles drying up after it rains.
What is boiling point?(cont.) • Vaporization that occurs below the surface of a liquid is called boiling. • When liquid boils, bubbles form within the liquid and rise to the surface.
What is boiling point? (cont.) • Boiling pointis the temperature at which a liquid becomes a gas. • Just like melting and freezing, while a substance is boiling, the temperature does not change. • At it’s boiling point, a substance absorbs energy and the energy causes the particles to move faster until they have enough energy to escape the liquid as gas particles. • Boiling ends after the liquid has changed to a gas. If energy continues to be added, then the temperature of the gas will continue to rise.
What is boiling point? (cont.) • The reverse of vaporization is condensation – a gas to a liquid. • As the gas cools, energy is released and its particles slow down • When particles move slowly enough for their attractions to bring them together, droplets of liquid form. • During condensation, the temperature of the substance does not change • After the change of state is complete, the temperature continues to drop.
What is boiling point? (cont.) • Every substance melts and boils at specific temperatures. • A material with high melting and boiling points has particles that are strongly attracted to one another. • A material with low melting and boiling points has particles that are weakly attracted to one another.
What is air pressure? • Air pressure is the force exerted by a gas. • Ex. Blowing up a balloon • The air particles move around rapidly inside the balloon and hit the inner surface of the balloon, exerting pressure on the balloon. • If you squeeze the balloon (increase the pressure), the balloon gets smaller (volume decreases).
What is air pressure? Ex. Blowing up a balloon (cont.) • If you put the balloon in the freezer (decrease temperature) and keep the pressure the same, the balloon gets smaller (volume decreases). • If you allow the balloon to sit out and warm up (increase temperature) and keep the pressure the same, the balloon will get bigger (volume increases).