Physical Properties

Physical Properties

• What are the physical properties of objects in this room?

• Physical Properties: are any characteristics that are to be described objects using the 5 senses– The five senses are:

• Sight• Taste• Touch• Smell• Hearing

Physical Properties

• For most objects the primary physical properties are:– Color, Shape, Smell, Taste, & even

Texture

• You probably became more aware of another property called: Density– this is a relationship of the amount of mass

per unit of space it takes up (space)

Physical Properties

• Here is an easy way to think of Density:– take two equal sized grocery bags– 1 full of potato chips– 1 full of canned food– They both take up the same space.– Which one is heavier?

• The one w/ the canned food

Physical Properties

• Look at oil & vinegar salad dressing

• You can always see the two distinct layers

• Density has another nice trick it can do.– identify other materials

Physical Properties

• How to measure density:– Density = mass/volume

Physical Properties

• States of Matter– There are 4 states of matter, we will only

be concerned w/ 3 of them:• Solids• Liquids• Gases

• These are fairly simple to understand and you’ve been dealing w/ them your entire life.

Physical Properties

• Regardless of what state of matter things like water are in their chemical formula is unchanged.

• The chemical formula for ice = H20

• The chemical formula for water = H20

• The chemical formula for steam = H20

Physical Properties

• Definitions of states of matter:1. Solid - a state of matter where the object

has definite shape & volume

2. Liquid - a state of matter where the object has definite volume but NO definite shape

3. Gas - a state of matter where the object has NO definite shape or volume

Physical Properties

• In solids the molecules are close together:

Physical Properties

• Liquids the molecules are a little further apart:

Physical Properties

• The molecules in gas are even further apart:

Physical Properties

• So far we have talked about:1. States of Matter

2. Density of matter

Now let’s talk about acids!

What do you think about when you hear the word acids?

ACID

• I think of the flesh dissolving liquids that have been the main method of trying to dispatch our heroes in so many of our iconic action movies. Yet, to only have them escape the aforementioned acid trap via a all too conveniently mis-tied strap by a henchman, and ultimately save the world and the girl. Thus belaying the evil mastermind’s conquest for world domination!– That’s for all of you that write word for word what I

put up on the screen.

ACIDS

• Not all acids will dissolve your car engine or your skin.– Ones like hydrochloric acid, phosphoric,

nitric, etc. are like that.– However ones like citric, carbonic and

other acids are actually beneficial to your body.

Physical Properties

• On the opposite end of the pH scale is bases.– Ammonia is an example of a base– A typical characteristic of bases that they

feel slippery. Like soap.– Also they taste extremely bitter

Chemical Properties

• So far we’ve found ways to describe matter using several physical properties:

• 1. State of matter

• 2. Density

• 3. pH scale

• 4. Other various observation

Chemical Properties

• When you strike a match what happens?– Phosphorus, wood, & oxygen all combine

to form new materials– the ability of some matter to burn is a

chemical property.– Chemical Property -> a characteristic of a

substance that allows it to change into a new substance

Chemical Properties

• Other chemical properties:– Oxidation– Toxicity– Flammablity– Reactivity

• this one is very interesting

Chemical Properties

• How come jewelers don’t make jewelry out of iron?– It is cheaper to mine an machine– The problem is that it rusts

• Every time you’d get sweaty the jewelry would be in jeopardy of rusting

– Iron is said to be very reactive– Unlike gold or silver which is unreactive

Chem. Prop. - vs. - Phys. Prop

• What are the differences between chemical properties & physical properties?– Chemical properties are a substance’s

willingness to change its form of matter. While physical properties, on the other hand, are those characteristics that an object possess and can be observed with the five senses.

Changes

• Just like properties there are chemical & physical changes.

• First, let’s discuss physical changes:– What do you think is a physical change?

• A physical change is any change in shape, size, and/or form.

• The MAIN thing is: what the substance is DOESN’T change.

Physical Changes

• What are some examples of physical changes?– Freezing (or freezing point) = when matter in a

liquid state cools to the point (a temp.) where it forms a solid

– Boiling (or boiling point) = when matter in a liquid state heats to the point (a temp.) where it becomes a gas.

• THESE ARE THE TWO MAIN PHYSICAL CHANGES MATTER GOES THROUGH!!!

Physical Changes

• Common boiling & freezing pointsFreezing Boiling

water 0C 100C

OceanWater -2C 115C

*The temperature at which these changes occurIs a physical property

There are other physical changes

• Condensation: when a gas cools to the point where it begins to form a liquid– It is actually the same as the boiling point– *Same could be said for the melting point &

freezing point.