MATTER PART 3

SO FAR, YOU’VE LEARNED WHAT MATTER IS MADE OF...ATOMS. YOU’VE

ALSO LEARNED ABOUT ELEMENTS.

NOW, WHAT IS A MOLECULE?

A MOLECULE IS TWO OR MORE ATOMS

THAT ARE CHEMICALLY JOINED

TOGETHER.

A MOLECULE IS TWO OR MORE ATOMS

THAT ARE CHEMICALLY JOINED

TOGETHER.

WHAT DOES THAT MEAN?

THAT MEANS THAT THE ATOMS ACTUALLY SHARE ELECTRONS.

Kind of like these dogs sharing a rope.

FOR EXAMPLE, SEVERAL GOLD ATOMS JOINED TOGETHER IS A MOLECULE.

H2O IS A MOLECULE.

IT’S GOT 2 HYDROGEN ATOMS AND 1 OXYGEN ATOM.

THE OXYGEN ATOM SHARES ITS ELECTRONS WITH BOTH

HYDROGEN ATOMS.

THIS IS A WATER MOLECULE.

NOTICE THAT THESE ELECTRONS ARE BEING SHARED.

SO, REMEMBER…

A MOLECULE IS 2 OR MORE ATOMS THAT ARE CHEMICALLY

BONDED.

WHAT DOES “CHEMICALLY BONDED” MEAN, AGAIN?

THAT’S RIGHT! THEY SHARE ELECTRONS!

HERE ARE SOME EXAMPLES OF MOLECULES:

1. Carbon dioxide - CO2

2. Water - H2O

3. Oxygen we breathe into our lungs - O2

4. Sugar - C12H22O11

5. Glucose - C6H12O6

6. Nitrous oxide - "Laughing gas" - N2O

7. Acetic acid - part of vinegar - CH3COOH

WHAT IS A COMPOUND?

FIRST OF ALL, A COMPOUND IS ALWAYS A MOLECULE.

WHAT MAKES A COMPOUND DIFFERENT FROM A MOLECULE:

A MOLECULE CAN BE EITHER THE SAME ATOMS CHEMICALLY BONDED OR

DIFFERENT ATOMS CHEMICALLY BONDED.

A COMPOUND IS ALWAYS MADE OF DIFFERENT ATOMS CHEMICALLY BONDED.

AND REMEMBER, A COMPOUND IS ALWAYS A MOLECULE, BUT A MOLECULE IS NOT ALWAYS A

COMPOUND. GOT IT?

IT’S LIKE SAYING A SQUARE IS A RECTANGLE, BUT A RECTANGLE IS NOT

A SQUARE.

AhaAha!

NOW WE KNOW THAT A CHEMICAL BOND IS WHEN ATOMS SHARE ELECTRONS, BUT WHAT IS A

CHEMICAL CHANGE?

https://youtu.be/37pir0ej_SE

SO, A CHEMICAL CHANGE OCCURS WHEN THE ATOMS THAT MAKE UP 2 OR MORE SUBSTANCES ARE REARRANGED TO FORM A NEW SUBSTANCE.

WHAT ARE INDICATIONS THAT A CHEMICAL CHANGE HAS OCCURRED?

THERE ARE 6 OF THEM.

1. THE SUBSTANCE HAS CHANGED COLOR.

2. THE SUBSTANCE RELEASES A SMELL, GOOD OR BAD.

3. THE CHEMICAL CHANGE MAY RELEASE LIGHT.

4. THE CHEMICAL CHANGE OFTEN RELEASES GASES.

The pockets are caused by carbon dioxide bubbles forming.

5. THE CHEMICAL CHANGE OFTEN GIVES OFF HEAT OR TAKES IN HEAT.

6. THE CHEMICAL CHANGE USUALLY CAN’T BE UNDONE.

The bread can’t be turned back into flour, milk, and butter.

SO, WE SAID WATER IS A MOLECULE. IS IT A COMPOUND, TOO?

YES.

IT’S A MOLECULE BECAUSE THE ATOMS ARE SHARING ELECTRONS...

...AND IT’S A COMPOUND BECAUSE IT’S MADE OF DIFFERENT ELEMENTS…

HYDROGEN AND OXYGEN.

WHAT’S A MIXTURE? WATCH THESE VIDEO TO LEARN:

https://youtu.be/jA0PzblYPUM?list=PL1RhBnRTmkY3M6sLlUsUHUq-i3docT7H2

WATCH THESE VIDEOS TO LEARN MORE ABOUT THE PROPERTIES OF

MATTER.

https://youtu.be/zD7W5O0BH7g

https://youtu.be/ZZYnERZe3Cg

SO, WHAT IS A MIXTURE? IS IT LIKE A COMPOUND?

NO!

A MIXTURE IS JUST DIFFERENT ATOMS FLOATING NEXT TO

EACH OTHER, BUT THEY ARE NOT CHEMICALLY BONDED!

HERE ARE SOME EXAMPLES OF MIXTURES:

ITALIAN SALAD DRESSING

Vinegar is a mixture of oil, vinegar, and seasonings.

CONCRETE

Concrete is a mixture of cement, rocks, and water.

SALT WATER

CAKE MIX

If you bake it in the oven, is it still a mixture?

THAT CONCLUDES THIS PRESENTATION ON MATTER.