1. CO2
Carbon Dioxide is the chemical most involved in global warming. It requires a large amount of energy to break the bonds. The sun’s rays vibrate the molecule warming the air around it. This creates a convection effect warming the planet.

2. Chemical Equation CH4 + 2 O2 → CO2 + 2 H2O
This is a combustion reaction
Carbon Compound (CH4) + O2  CO2 + 2 H2O

3. Molar Mass
CO2
Carbon has an atomic mass of 12 a.m.u.
O has an atomic mass of 16 a.m.u.
There are 2 Oxygen atoms in CO2
2 X 16 = 32
= 44

4. Dot Diagram Each dot represents a valence electron
C O O
Each bond requires 2 electrons.
Each bar represents a bond.
O C O

5. O C O Bond Types There is only one type of bond in this chemical
Oxygen / Carbon double bond
Both of these atoms are non-metals
When non-metals bond they form covalent bonds.

6. Electronegativity Ionic 1.7 - 4.0 Polar Covalent 0.5 - 1.69
Non-Polar Covalent – 0.49
(Oen - Cen) 3.55 – 2.55 = 1 Polar covalent bond Oxygen holds electrons tighter than Carbon

7. Bond Energy Calculating Enthalpy Reactants Products
Bonds breaking are negative and bonds forming are positive
CH4 + 2 O2 → CO2 + 2 H2O
C-H O=O C=O H-O
Reactants
-424 x4 = (C-H)
-495 x2 = (O=O)
(kJ/mol)
Products
1072 x2 = (C=O)
463 x2 = (O-H)
3070 (kJ/mol)
Exothermic: energy is released
enthalpy of reaction is negative
Endothermic: energy is absorbed
enthalpy of reaction is positive

8. Endothermic vs Exothermic
Exothermic: energy is released
enthalpy of reaction is negative
Endothermic: energy is absorbed
enthalpy of reaction is positive
Reactants
-424 x4 = (C-H)
-495 x2 = (O=O)
(kJ/mol)
Products
1072 x2 = (C=O)
463 x2 = (O-H)
3070 (kJ/mol)
SUM (BEreactants) - SUM (BEproducts) = Hreaction
= (kJ/mole)
384 is a positive (+) number
This is an exothermic reaction