Properties of Matter
Changes in Matter
Chemistry: is the study of matter (chemicals) and the changes it undergoes
2 TYPES OF CHANGES:
Physical Changes
Physical Change - DOES NOT alter the identity! Can change state, size, or shape of a substance
Chemical Change
Chemical Change: produces new substance with new properties
Key note: Chemical changes produce a new substance!!!
Try It!
As I click through the next few slides, give a thumbs up if you believe a physical change is being described. If you think a chemical change is being described, touch your nose.
Change of State
Dry ice undergoes something called sublimation – which means it goes directly from a solid to a gas, without ever existing in liquid form.
PHYSICAL
Burning
One of the hottest chemical reactions known to man is the combustion of dicyanoacetylene in ozone, which reaches 5500K – close to the temperature of the surface of the sun!
CHEMICAL
Alloying
Gold and other metals in jewelry are measured in carats – which tells you how much pure gold is in the jewelry. Because gold is very soft, it is often mixed with other metals in jewelry.
PHYSICAL
Cutting Wood
The largest tree in the world is a Giant Sequoia known as “General Sherman” – it is 275ft tall, over 100ft wide, and 2,200 years old!
PHYSICAL
Rusting
The process that causes cut apples to turn brown is an oxidation reaction similar to the rusting of metal.
CHEMICAL
Physical Chemical
Properties of Matter
Key note: Properties are just descriptions!
Try It!
As I click through the next few slides, give a thumbs up if you believe a physical property is being described. If you think a chemical property is being described, touch your nose.
Color
Fun fact: hydrangeas will be different colors depending on the nutrients they absorb through the soil!
PHYSICAL
Flammability
Pure hydrogen peroxide is flammable enough to burst into flames at room temperature!
CHEMICAL
Hardness
Diamonds are a form of carbon that has been highly compressed into a unique lattice structure. It’s name comes from the Greek word ‘adamas’ meaning “unbreakable”.
PHYSICAL
Density
Ice is actually less dense than its liquid equivalent (water), which is why it floats. Most substances are actually more dense as a solid than their liquid counterpart.
PHYSICAL
Reactivity
Pure fluorine is the most reactive element we know of. This is because of its high electronegativity.
CHEMICAL
Physical Chemical
Intensive Properties
Extensive Properties
Try It!
For every intensive property you see, give a thumbs up.
For every extensive property you see, touch your nose.
Mass
The most weight ever lifted at the Olympics was 263 kg, a record set four years ago in Beijing!
EXTENSIVE
Boiling Point
The Celsius scale is based on the freezing point and boiling point of water.
INTENSIVE
Refractive Index
Pink Floyd’s “Dark Side of the Moon” album cover is one of the most widely recognized images in music – after the Beatles’ “Abbey Road”
INTENSIVE
Thickness
This soap bubble screen is being used to display a video– creating the world’s thinnest display ever known!
EXTENSIVE
Density
Iridium is the world’s densest element – it’s calculated density is 22.65 g/cm3
TWICE THE DENSITY OF LEAD!
INTENSIVE
Intensive Extensive
Talk About It
Partner 1: What is an intensive property? Give one example.
Partner 2: What is an extensive property? Give one example.