Physical Properties Demonstration Why is there a difference in the behavior of the two cans of soda? (Hint: think about what is contained in each can.) Why is there a difference in the behavior of the two cans of soda? (Hint: think about what is contained in each can.)

Density Demonstration Density = mass/volume Assume the density of H 2 O = 1g/mL Estimate what is the density of diet soda? What is the density of regular soda? Which can weighs more? How do you know?

The early Earth Density of Elements and Compounds has, in a large part determined their distribution on the planet Volcanic gases include: H, O, HO, CO (carbon dioxide), N 2, CO (carbon monoxide), Volcanic gases include: H 2, O 2, H 2 O, CO 2 (carbon dioxide), N 2, CO (carbon monoxide),

Given these densities, which gases in the early earth do you think stayed close to the planet and which escaped into space? Why? Density (g/mL) Hydrogen (H 2 )8.988 x Nitrogen (N 2 )1.25 x Carbon Monoxide (CO)1.25 x Carbon Dioxide (CO 2 )1.977 x Hydrochloric Acid (HCl) x Which important gas present on earth today is missing from this list?

Carbon Cycle Carbon is exchanged between the atmosphere and the land and water reservoirs on Earth. The existing cycles remove about as much carbon as they add, but human activity is currently increasing atmospheric carbon by about 3 bmt per year Carbon is exchanged between the atmosphere and the land and water reservoirs on Earth. The existing cycles remove about as much carbon as they add, but human activity is currently increasing atmospheric carbon by about 3 bmt per year

Chemical Reactions  Photosynthesis  Carbon dioxide in the atmosphere is converted into sugar.  Solar energy + 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Carbon Dioxide WaterSugar Oxygen  The solar energy is converted into stored chemical energy in the form of sugar

Chemical Reactions continued Chemical reactions involve a rearrangement of atoms as they change from one substance to another Chemical reactions involve a rearrangement of atoms as they change from one substance to another Use formulas rather than names Use formulas rather than names Starting materials on left, products on right Starting materials on left, products on right  means yields  means yields + means reacts with + means reacts with Atoms on left must equal atoms on right Atoms on left must equal atoms on right

Photosynthesis: a chemical reaction  6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Balanced? Balanced?

Reaction of Mg and HCl Where did the Mg go? Where did the Mg go? What evidence do you have that a reaction took place? What evidence do you have that a reaction took place?Reaction:

Balancing Reactions Balance: Balance: Na + Cl 2  NaCl Na + Cl 2  NaCl NO 2 + H 2 O  HNO 3 + NO NO 2 + H 2 O  HNO 3 + NO KI + Pb(NO 3 ) 2 KI + Pb(NO 3 ) 2