Chapter 15Properties of Matter

Classifying Matter• Matter is a term used to describe any

material that has mass and takes up space.

• Matter can be classified as either a mixture or a substance.– Substances can either be elements or

compounds.• Matter has different characteristics such

as: boiling and melting temperatures, hardness, density, elasticity

What is A Mixture?• A mixture is made out of more than

one kind of matter• An example is soda, because it can

be separated into carbonated water, corn syrup, caramel color, phosphoric acid, natural flavors and caffeine

• There are two types of mixtures, heterogeneous and homogenous

Types of Mixtures• A Homogeneous mixture is the same throughout. All

samples of this type of mixture would be the same. Examples: soda, salt water, brass (a mixture of copper and zinc)– A solution is a type of homogeneous mixture with particles

that are so small they cannot be seen with a microscope. Made with water (solvent) and a solute such as salt

– An alloy is a solid mixture, such as brass. You must melt the metals to mix them

• A Heterogeneous mixture has different parts that are visible in the mixture. Examples: Chicken noodle soup, M&M’s, Chex mix

• Sometimes heterogeneous mixtures are hard to see (a cotton polyester blend shirt for example)

Colloids• A colloid is a mixture with larger

particles than in a solution, but not heavy enough to settle out. (ex.- milk, fog)

• Detected by the Tyndall Effect, in a colloid light beams are scattered and you can see the beam easily

Suspensions• Heterogeneous mixture in which

large particles settle• Muddy pond water• They do scatter light like colloids, but

the particles are much larger and some actually settle out of solution

Mixtures vs. Substances• Mixtures can be separated into different

types of matter by physical means• Substances cannot be separated easily• Substances include:– Elements- The smallest sample of matter,

contains only one type of atom (silver, oxygen)– Compounds: Two or more elements joined

together chemically and cannot be separated by physical means ( water, salt, sugar)

Properties of Matter• Physical Properties – characteristics

of a material which can be observed without changing the identity of the material.(size, shape, color)

• Chemical Properties – characteristics of a substance indicating that it can change chemically. (flammability)

Properties of Solids

Hardness• Resistance to

scratching• Talc is the softest –

baby powder • Diamond is the

hardest

Elasticity• Ability to stretch

and return to the original form

• Gives the ability to bounce and withstand an impact

Brittleness• Tendency to shatter

on impact - glass• Safety glass is coated

with cellulose nitrate• Enhanced protective

glass – two pieces of glass with Saflex in between – used in cars and as a sound barrier

Malleability• Solids ability to

be pounded into sheets

• Aluminum foil

Ductility • Ability to be pulled

into thin wire• Gold and silver

Tensile strength• A measure of how much

tension or pulling that a material can withstand

• Strength of rope, fiber, and cables

• Kevlar - is constructed of para-aramid fibers which are five times stronger than the same weight of steel, while being lightweight, flexible and comfortable. It is also very heat resistant and decomposes above 400 °C without melting.

More Properties of Solids• Boiling point• Melting point• Color• Conductivity• Mass• Odor• Shape• State of Matter

Measuring Matter• Mass- amount of matter

in an object• Measured in grams or

Kg• Use a triple beam or

electronic balance to determine

• You can get the mass of a liquid by massing it in the container and subtracting the mass of the container

Volume• Volume- Amount of

space something takes up

• Volume of a liquid- use a graduated cylinder

• Volume of a solid- lxwxh

• Displacement

Displacement• Use the

displacement of liquid in a graduated cylinder to determine the volume of an object

• Useful for small, irregularly shaped objects

How to measure volume using displacement

• Pour an even volume of water into a graduated cylinder

• Read the volume • Drop the object in the water• Read the volume• Subtract to get the volume of the

object

Density• Relationship between

mass and volume• Tells us how tightly the

atoms or molecules in a material are packed together

• Higher density – atoms are closer together

• Lower density- atoms farther apart

• Size and shape do not effect density

M

D V

Density• You must have the

volume and the mass to calculate density.

• A material’s density is a physical property and stays the same for that particular material, but can vary due to state of matter and temperature

• Units:• Mass in kg or g• Volume in cm3 or

mL• Density in g/cm3,

g/mL, kg/cm3, kg/mL

• Most of the time will be the first two

Density and Temperature• As the temperature increases,

density decreases• A solid that is warm will have a

slightly lower density than a solid that is cold

• The same is true for gases and liquids

Density of liquids• In liquids the volume increases

because the molecules are moving more quickly

• The volume increases so density decreases

• Liquid silver is less dense than solid silver

• Water is an exception– ice floats on water

• Solid water is less dense than liquid– this is important in nature

Density Lab• While vacationing

in California, you find a large chunk of metal that appears to be gold. How can you make sure you struck it rich without letting anyone else know about the find?

Lucky you, you remember that all materials have a density that is

specific to themselves.

• So the first thing you do is look up the density of gold.

So then you measure the mass of your sample.

193.0 g

So then you measure the volume of your sample.

• Unfortunately the sample is an odd shape, but you remember from your physical science class how to measure volume by the displacement method.

Do you have Gold?

YES!!!!!!Now, let’s see how rich you

are.Gold is currently selling at

$1,664.00 / ounce1 ounce = 28.35 grams