CHEMISTRY: STRUCTURE OF MATTER

THE STRUCTURE OF MATTER What is matter? – Matter is anything that takes up space and has mass All matter is made up of atoms Just one kind of element is called an element Elements can be found on the periodic table

SUBSTANCES All matter is made up of atoms Just one kind of atom is called and element Elements can be found on the periodic table

5 The Periodic Table lists every known element in the universe!

6 Is this substance an element? No, because it is made of more than 1 kind of atom.

7 Is it an element now? No, because it is made of more than 1 kind of atom.

8 Is it an element now? Yes! Because it is made of only one kind of atom.

9 Gold is made of only gold atoms. Is gold an element? YES!

10 Water is made up of two kinds of atoms bonded together. Is water an element? NO!

11 Water is NOT an element! It is made of more than one kind of atom. Water is a molecule of hydrogen and oxygen atoms bonded together.

ATOMS VS. COMPOUNDS What is the smallest particle an element could be divided into and still retain the properties of that element? an ATOM Atoms make up molecules, which is defined as two or more atoms bonded together. for example: CO 2 and H 2 O are compounds.

Which ones are an atom? Which ones are elements? Which ones are compounds? a)b) c) d) Check yourself

Which ones are an atom? c Which ones are elements? a, c, d Which ones are compounds? b a)b) c) d) Check yourself

MIXTURES Two or more substances are called a mixture Homogeneous - all the same Heterogeneous – different substances BrainPop: Compounds and mixtures

TRICKY MIXTURES Solution: very small particles; light can pass through Colloid: larger particles, light gets scattered – they appear murky or opaque. Examples: milk and fog Suspension: Even larger particles, light cannot get through and they appear very murky. They will eventually separate like oil & water, and can be filtered to separate compounds. Examples: salad dressings, blood, and aerosol sprays

NOTES SUMMARY: What is the difference between a compound and a mixture?

BASIC CHEMISTRY Everything is made up of these 2 things: Matter and Energy Matter – has mass and occupies space Energy – ability to do work

MATTER Can change forms It can be a liquid, solid, or gas

BASIC CHEMISTRY Energy can change forms: Solar cells change light to electrical energy, Steam Engine Heat to Motion (Kinetic Energy) UP Steam Engine

Cells convert (food) chemical energy to cellular energy. ENERGY

PRINCIPLE OF CONSERVATION OF MASS Mass cannot be created nor destroyed. It just changes forms. Example: burning a log After it has burned, the log is lighter. What happened? Some of the mass was converted from solid to gas.

PRINCIPLE OF CONSERVATION OF ENERGY Energy cannot be created or destroyed – Applies only to normal chemical reactions, NOT nuclear reactions. In nuclear reactions, energy and mass can be destroyed or created. E=MC 2 E is energy, M is mass, C is the speed of light MASS IS CHANGED INTO ENERGY in nuclear reactions

SIDE NOTE: THE NATURE OF SCIENCE These last 2 principles used to be referred to as “Laws” – meaning it was thought to be an absolute fact. Nuclear theory blew that idea out of the water – literally. This is why it is important for scientists to be cautious about their conclusions. They say “This is our current belief on a specific principle, based upon the evidence collect so far”. It’s why we say “our hypothesis was supported” instead of “right”