Zoom into Air
Large Scale
2
Air contains rain drops
1 cm
Macro Scale
3
Air also contains water droplets
Macro Scale
4
Single cloud droplet
Micro Scale
5
When we zoom in even smaller….
H2O
…. we still see
water!
Atomic-molecular Scale
6
Other Molecules in Air
Oxygen
O2
Water
H2O
Nitrogen
Carbon dioxide
N2
CO2
Atomic-molecular Scale
7
What’s in our atmosphere’s air?
Nitrogen (78%)
Oxygen (21%)
Argon (0.9%)
Carbon dioxide (0.03%)
Water (variable)
8
What is the difference between an
atom and a molecule?
1.
2.
3.
Oxygen
Carbon dioxide
Argon
4.
5.
6.
Nitrogen
Oxygen
Hydrogen
7.
8.
9.
Carbon
Nitrogen
Water
9
Enter: “Chemical Change Notes” into
your journal’s Table of Contents
10
Three Facts about Atoms
1. Atoms last forever (except in nuclear
changes).
2. Atoms make up the mass of all materials.
3. Atoms are bonded to other atoms in
molecules.
11
Two Questions about Chemical Change
• A chemical change is:
– A change in matter where atoms are rearranged into
new molecules.
• Scientists try to answer these questions about
chemical changes that involve carbon atoms:
– Location: Where are atoms moving? (Where are
atoms starting? Where are they moving to?)
– Carbon: What is happening to carbon atoms? (What
molecules are the carbon atoms in before the
chemical change? How are the atoms rearranged into
new molecules?)
12
Class Data Chart
Time (min.)
Change in mass: Soda
Water
Our data
Time (min.)
Class Avg
Change in mass: Regular
Water
Our data
0-5
0-5
5-10
5-10
10-15
10-15
Class Avg
Soda Fizz Lab Graph
Change in Mass
0.10
0.05
0.00
-0.05
-0.10
-0.15
5
10
Minutes
15
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Chemical Change = A change in matter where
atoms are rearranged into new molecules.
Soda Water Fizzing
Water Evaporating
Soda water was undergoing a chemical change
because….
What happens when soda water loses its fizz?
Where are atoms moving from?
Where are atoms moving to?
Chemical
change
What molecules are carbon atoms in
before the change?
What other molecules are involved?
What molecules are carbon atoms in
after the change?
What other molecules are involved?
Remember: Atoms last forever (so you can rearrange atoms into new molecules,
but can’t add or subtract atoms)