Barrel

1

Barrel

Gas Inlet

Gas Control Valve

Base

Air Valve/Intake

http://upload.wikimedia.org/wikipedia/commons/7/70/Bunsen_Burner_(PSF).jpg

Bunsen Burner & Gas Valve

2

High Heat

Low Heat

http://www.greece.k12.ny.us/oly/chemistry/Chemistry%20Icons/Lab%20Apparatus/burner%20parts.jpg

No Yes

The Flame

• Gas Valve for Adjusting Flame

• Iron ring very HOT!!!

• Gas off when burner not lit

3

ExperimentalSet Up

• Vent Crucible Lid

• Crucible Very Hot

VENTED

4

• Crucibles EXTREMELY hot. • Crucible tongs to transfer. • Cooling on gauze.• Mass when cool to the touch.• Mass the lid AND the

crucible.

5

• All atoms of same element are the same.• Different element atoms are different.• Compounds have fixed whole number ratios.

– Water is always H2O

CONSTANT COMPOSITION

8 P

8 N12 P

12 N

I thought I was magnesium?!?

Hi, I’m Magnesium

!

6

• Impossible to measure mass of oxygen

• The sum of the parts equals the whole

• Conservation of Mass

Metal + Oxygen Metal Oxide

Mass 1 (Mass 2 – Mass 1) Mass 2

Law of Conservation

Metal Oxide - Metal Oxygen

7

• First Heating– Magnesium + Oxygen Magnesium Oxide– Magnesium + Nitrogen Magnesium Nitride

• Second Heating (Low Heat)– Magnesium Nitride + Water Magnesium

Hydroxide + Ammonia

• Second Heating (High Heat)– Magnesium Hydroxide Magnesium Oxide

+ Water

Reactions Occurring

8

• Oxygen is 16 amu or grams/mol.

• The calculations can not be completed until experiment is finished.

• Roman numerals from table.

( )100 ______ %

( )

amuOOxygen

amuMgO

VI

V

( ) (2 )

( ) 16

amuMg x amuMg

amuO

IV

VI amuO

( ) ( )

( ) 16

and

( ) ( )

( ) (2 16)

amuMg x amuMg

amuO amuO

amuMg x amuMg

IV

VI

IV

VI amuO amuO

Calculations

9

Magnesium Uses• Melting point of

1202°F (650°C) • Boiling point of

1994°F (1090°C).• Never use H2O or

CO2 extinguishers to put out Mg fire

• Alloys– Artificial limbs– Vacuum cleaners– Optical instruments– Skis