the properties of matter chapter 2. problem solving scientists will often use an object’s...

The Properties of Matter

Chapter 2

Problem Solving

•Scientists will often use an object’s properties to best help them solve a problem

Section 1: What is Matter?

•Objectives▫Define and describe the two properties of all matter▫Identify the tools and units used to measure volume

and mass▫Calculate the volume of a regular-shaped object

with a formula▫Calculate the volume of an irregular-shaped object

with the water displacement method▫Compare and contrast mass and weight▫Explain the relationship between mass and inertia

Section 1: What is Matter?

•We are made of matter▫Matter is anything that has mass and takes up space

Section 1: What is Matter?

•Is it matter?▫Toaster▫Bowl of soup▫Steam▫Sound▫Dust▫Air▫Heat▫Flag▫Bacteria▫Light

Section 1: What is Matter?•How much space does matter take up?

▫It depends▫We call it volume

Volume is the amount of space taken up, or occupied, by an object

Section 1: What is Matter?

•Liquid volume▫Often use units like

the Liter (L) and milliliter (mL) 1000 mL = 1 L

▫Use a graduated cylinder to measure Read along

meniscus bottom Meniscus is a

curve at a liquid’s surface

Measuring volume of a liquid using a graduated cylinder

Section 1: What is Matter?

•Volume of solids▫Regular shape—use a formula

▫Irregular shape—water displacement method Measure water volume Measure new volume with object Find difference

VOLUME = LENGTH X WIDTH X HEIGHT

Volume of a irregular shaped object with water displacement

Section 1: What is Matter?

•How will we do math problems in physical science?

•4 steps

1. Write the formula2. Identify the variables3. Put numbers in equation4. Solve for the answer, circle answer

Section 1: What is Matter?

•Sample problem: What is the volume of a box that has a length of 5 cm, a width of 1 cm, and a height of 2 cm?

•Step 1: Write the formula

V= L x W x H

Section 1: What is Matter?

•Sample problem: What is the volume of a box that has a length of 5 cm, a width of 1 cm, and a height of 2 cm?

•Step 2: Identify the variables

5 cm1 cm2 cm

Section 1: What is Matter?

•Sample problem: What is the volume of a box that has a length of 5 cm, a width of 1 cm, and a height of 2 cm?

•Step 3: Put numbers in the equation

V= 5 cm x 1 cm x 2 cm

Section 1: What is Matter?

•Sample problem: What is the volume of a box that has a length of 5 cm, a width of 1 cm, and a height of 2 cm?

•Step 4: Solve and circle answer

NO NAKED NUMBERS!!

V= 5 cm x 1 cm x 2 cmV= 10 cm3

Section 1: What is Matter?

•Matter and Mass and Weight▫Mass is the amount of matter in an object

It is the same everywhere in the universe!

▫Weight is a measure of the gravitational force exerted on an object The more mass, the more weight Varies by its location in the universe

Mass versus Weight

Section 1: What is Matter?•Differences between Mass and Weight

Mass Weight

Measure of amount of matter in an object

Measure of the gravitation force on an object

Always constant for an object no matter where it is

Varies depending on where the object is on the Earth or the universe

Measured using a balance (shown below)

Measured using a spring scale (shown at right)

Expressed in kilograms (kg), grams (g), and milligrams (mg)

Expressed in newtons (N)

Mass versus Weight song

Section 1: What is Matter?•Inertia

▫Inertia is the tendency of an object to resist a change in motion The more mass an item has, the more inertia

it will have

Inertia

Section 1: What is Matter?

• Section Review▫Please answer the objectives on your objective

summary sheet

1. Define and describe the two properties of all matter2. Identify the tools and units used to measure volume

and mass3. Calculate the volume of a regular-shaped object with

a formula4. Calculate the volume of an irregular-shaped object

with the water displacement method5. Compare and contrast mass and weight6. Explain the relationship between mass and inertia

Section 2: Physical Properties

•Objectives▫Identify six examples of physical properties

of matter▫Describe how density is used to identify

substances▫Calculate density using a formula▫List examples of physical changes▫Explain what happens to matter during a

physical change

Section 2: Physical Properties

•Let’s play 20 Questions!QUESTIONS QUESTIONS

Section 2: Physical Properties•Physical properties are great for the game•Physical properties are great for

describing matter▫Physical properties are traits that can be

observed or measured without changing the matter’s identity

Section 2: Physical PropertiesThermal conductivity is

the rate at which a substance transfers heat.

Plastic foam is a poor conductor

State is the physical form of the substance, such as solid, liquid, or gas. Ice is

water in the solid state

Density is the mass per unit volume of a substance. Lead is very dense, so it makes a good sinker for a fishing line

Solubility is the ability of a substance to dissolve in

another substance. Flavored drink mix dissolves in water.

Ductility is the ability of a substance to be pulled into

a wire. Copper is often used to make wiring

because it is so ductile

Malleability is the ability of a substance to be rolled or pounded into thin sheets. Aluminum can be rolled into sheets to make foil

Section 2: Physical Properties

•Density▫Describes the relationship between mass

and volume Density is the amount of matter in a given

amount of space, or volume

GOLF46 grams

PING PONG2 grams

Section 2: Physical Properties

•Solving for Density (d)

•Density can help identify substancesDensities of Common Substances

SUBSTANCE DENSITY (g/cm3) SUBSTANCE DENSITY (g/cm3)

Helium (gas) 0.00001663 Zinc (solid) 7.13

Oxygen (gas) 0.001331 Silver (solid) 10.50

Water (liquid) 1.00 Lead (solid) 11.35

Pyrite (solid) 5.02 Mercury (liquid) 13.55

DENSITY = MASS VOLUME

Density song from our friend!

Section 2: Physical Properties

•Sample problem: What is the density of an object whose mass is 25g and whose volume is 10 cm3?

•Step 1: Write the formula

DENSITY = MASS

VOLUME

Section 2: Physical Properties

•Sample problem: What is the density of an object whose mass is 25g and whose volume is 10 cm3?

•Step 2: Identify the variables

25 g10 cm3

Section 2: Physical Properties

•Sample problem: What is the density of an object whose mass is 25g and whose volume is 10 cm3?

•Step 3: Put numbers in the equation

DENSITY = 25 g 10 cm3

Section 2: Physical Properties

•Sample problem: What is the density of an object whose mass is 25g and whose volume is 10 cm3?

•Step 4: Solve and circle answer

NO NAKED NUMBERS!

!

DENSITY = 25 g 10 cm3

Density= 2.5 g/cm3

Section 2: Physical Properties

•The formula triangle

•Cover up the piece you want to solve for

•Find the new equation

•M =

•V =

D x V

M D

Section 2: Physical Properties•Sample problem: Suppose you have a lead

ball whose mass is 454 g. What is the ball’s volume?

•Step 1: Write the formula

V= M D

Section 2: Physical Properties•Sample problem: Suppose you have a lead

ball whose mass is 454 g. What is the ball’s volume?

•Step 2: Identify the variables454 g11.35 g/cm3

Densities of Common Substances

SUBSTANCE DENSITY (g/cm3)

SUBSTANCE DENSITY (g/cm3)

Helium (gas) 0.00001663 Zinc (solid) 7.13

Oxygen (gas) 0.001331 Silver (solid) 10.50

Water (liquid) 1.00 Lead (solid) 11.35

Pyrite (solid) 5.02 Mercury (liquid)

13.55

Section 2: Physical Properties

•Sample problem: Suppose you have a lead ball whose mass is 454 g. What is the ball’s volume?

•Step 3: Put numbers in the equationV= 454 g

11.35

g/cm3

Section 2: Physical Properties

•Sample problem: Suppose you have a lead ball whose mass is 454 g. What is the ball’s volume?

•Step 4: Solve and circle answer

NO NAKED

NUMBERS!!

V= 454 g 11.35 g/cm3

V= 40 cm 3

Section 2: Physical Properties

•Physical Changes do not form new substances▫A physical change is a change that affects

one or more physical properties of a substances

Section 2: Physical Properties

•Examples of physical changes▫Freezing water▫Sanding wood▫Dissolve sugar in water▫Melting butter

Section 2: Physical Properties

•Matter and physical changes▫Physical changes to not change the identity

of the matter involved Ice is still water Sawdust is still wood Melted butter is still butter Shaped clay is still clay Cut paper is still paper

Section 2: Physical Properties• Section Review

▫Please answer the objectives on your objective summary sheet

1. Identify six examples of physical properties of matter

2. Describe how density is used to identify substances

3. Calculate density using a formula

4. List examples of physical changes

5. Explain what happens to matter during a physical change

Section 3: Chemical Properties

•Objectives▫Describe two examples of chemical

properties▫Explain the importance of characteristic

properties▫Explain what happens during a chemical

change▫Distinguish between physical and chemical

changes

Section 3: Chemical Properties

•Chemical properties▫A chemical property describes matter

based on its ability to change into new matter that has different properties

Section 3: Chemical Properties

•Chemical Properties▫Flammability is the ability of a substance to

burn

▫Reactivity is the ability of two or more substances to combine to form one or more new substances

Section 3: Chemical Properties

•Physical versus Chemical propertiesPhysical Property Chemical Property

Shape Bending an iron nail will change its shape

Reactivity An iron nail can react with oxygen in the air to form iron oxide (rust)

State Rubbing alcohol is a clear liquid at room temperature

Flammability Rubbing alcohol is able to burn easily

Section 3: Chemical Properties

•Physical versus Chemical properties▫How do you tell?

Chemical—substance changes into something new by observing property

Physical—does not change identity by observing property

Section 3: Chemical Properties

•Characteristic Properties▫Characteristic properties are the properties

that are most useful in identifying a substance Do not change regardless of sample size

Density, solubility, flammability, reactivity

▫How do I know what is in this beaker???? (tomorrow)

Section 3: Chemical Properties

•Chemical Changes and New Substances▫A chemical change is when one or more

substances are changed into new substances that have new and different properties Not the same as a chemical property!

Bill Nye Chemical Change

Section 3: Chemical Properties

•How do we know a chemical change is occurring?▫Change in color or odor

Section 3: Chemical Properties

•How do we know a chemical change is occurring?▫Formation of a gas (fizzing and foaming)

Section 3: Chemical Properties

•How do we know a chemical change is occurring?▫Sound or light being given off

Section 3: Chemical Properties

•Physical and Chemical Changes

Change in texture Grinding baking soda into a fine, powdery substance is a physical change

Reactivity with Vinegar Gas bubbles are produced when vinegar is poured into baking soda

Section 3: Chemical Properties

•Physical versus Chemical Changes▫How do I know which is which?

▫DID THE CHEMICAL COMPOSITION CHANGE? If yes, it’s chemical If no, it’s physical

Section 3: Chemical Properties

•Can changes be reversed?▫Sometimes!

▫Ice water ice againREVERSIBLE

▫Eggfried egg IRREVERSIBLE

The Properties Song!!!

Section 3: Chemical Properties• Section Review

▫Please answer the objectives on your objective summary sheet

1. Describe two examples of chemical properties

2. Explain the importance of characteristic properties

3. Explain what happens during a chemical change

4. Distinguish between physical and chemical changes