chemistry review. atoms/elements/molecules what is the difference between an atom and an element?...

Chemistry Review

Atoms/Elements/Molecules

• What is the difference between an atom and an element?

• What is the difference between an element and a compound/molecule?

• What is an example of an element?

Matter

• What are the 3 states of matter?• SOLID, LIQUID, GAS• Animation

Phase Changes

SOLID LIQUID GAS

Properties

• What is a property?• Describes, talks about it’s ability to…• Can be physical or chemical• Physical property: characteristic/ability of a

substance without changing it to something new• Chemical property: characteristic of a substance

that does has the ability to turn into something new

Physical & Chemical Characteristics

PHYSICAL CHEMICALChanges its appearance physically

Changes what it is made up of (can change the atoms to make a new thing); reacts

Examples of Properties

• Front Desk:PHYSICAL PROPERTIES CHEMICAL PROPERTIES

Color FlammableHardness Could change color if burnedAbility to breakMelting point of plasticNot flexibleNot magneticTexture

9/11 – notes stop here

9/17 Notes start Changes

• When it actually changes• Physical: changes size, shape, color but its still

the same thing• Chemical: changes what it completely is,

chemical reactions

Examples of changes

• Tearing paper• Burning paper• Breaking wood• Campfire• Mixing kool aid• Cooking a cake

Physical change

Physical change

Physical change

Chemical change

Chemical change

Chemical change

Property vs. Change

• Property = description or could change in the future• Change = change• 5 evidences of a chemical change• PCOGT – “Pirates can obtain great treasures”– Precipitate (solid forms)– Color change– Odor(smell)– Gas forms– Temperature change– Evidence of a chemical change– http://resources.educ.queensu.ca/science/main/concept/gen/g09/N.%20Sabet/precipitation.jpg

Property or Change?

• Boiling point• 2 different liquids mix bubbles• Food coloring in water• Burning an egg• It has a yellow color• It produced a smell

Property

Property

Property

Change

Change

Change

• Which of the following is an example of a chemical property of water?– A. Boils at 100 C– B. Is transparent– C. Has no odor– D. Reacts with calcium

Is it still water (H2O)

Transparent = see through/clear

No smell

Reacts = chemical reaction

• Which of the following is an example of a physical property of hydrogen? It

• A. Is less dense than air• B. Reacts with oxygen• C. Is highly flammable• D. Forms hydrochloric acid

PHYSICAL PROPERTY

Energy that can be given off in a chemical reaction

• 3 different kinds• Substance gets warmer?• HEAT ENERGY• Changes color?• LIGHT ENERGY• Creates a noise?• SOUND ENERGY

Common Chemical reactions

• Respiration• Rust• Photosynthesis• Combustion: 2 chemicals burning

How can you speed up a chemical reaction?

• Add heat• Stir• Crush

Don’t freak out

• Take your time• Use tools• Read the entire question• Look at the graphs and tables