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