1. Plan for the period Correct p.41 Correct first page of handout
NOTES – chemical reactions
Homework: lab on neutralization, finish handout on balancing chem. equations, p.53 and p.54

2. Organization of matter
Pure substances
Elements
Compounds
Mixtures

3. Chemical Reactions (p.117-124)
21/10/99
Certain chemicals combine with other chemicals to form new chemicals.
Chemicals may also be broken down into their parts.
2K + Cl2 ---> 2KCl
FeS ---> Fe + S
Zn + 2HCl ---> ZnCl2 + H2
Zn + 2HCl ---> ZnCl2 + H2
Reactants
Products

4. 21/10/99
Chemical Reactions
In a chemical reaction, a chemical change must take place.
 Evidence: Release of energy as heat and/or light, change in colour, formation of gas, change in odour, etc.
iron + oxygen  iron(III) oxide

6. 1st type Acid-Base Neutralization
Solutions can be acidic or basic
When you combine an acid with a base, the result is salt and water.
Examples:
HCl + NaOH  H2O + NaCl
HBr + KOH  H2O + KBr

7. This is called NEUTRALIZATION (p.119)
REMEMBER:
An acid is characterized by the presence of H+ (hydrogen ions) and a base is characterized by the presence of OH- (hydroxide ions).
If we mix an acid and a base to the point where the number of H+ and OH- ions becomes equal, we have neutralization.
If [H+] = [OH-], the solution is neutral. (pH= 7)

9. Writing out neutralization equations
Ex1) sodium hydroxide + hydrochloric acid  sodium Chloride + water
NaOH + HCl  NaCl + H2O
Ex 2) sulfuric acid + potassium hydroxide  potassium sulfate + water
H2SO KOH  2 2
H2O +
K2SO4
Remember compounds form between positive metals and negative non-metals or negative polyatomic ions.
1) Since it is a neutralization reaction, we know that water will be formed. That gets rid of the H’s and the O’s (don’t worry about balancing yet). All we are left with is: SO4-2 and K+1
2) Do cross over rule: K+1 SO4-2
K2 SO4
K2SO4
3) Balance equation if necessary.

10. Your turn! – Now, read page 119
HCl(aq) + Ca(OH)2(aq) 
H3PO4(aq) + NaOH(aq) 
HClO3(aq) + LiOH(aq) 
Mg(OH)2(aq) + HBr(aq) 

11. COMBUSTION! 2nd type Combustion How does refined oil create energy?
FUEL + OXYGEN  CARBON DIOXIDE + WATER + ENERGY

12. Black Gold

13. What is a fossil fuel?
Natural substances made deep within the earth from the remains of ancient plants and animals
Over time, heat & pressure turned decomposing remains into fuels, which release energy when burned
Coal, oil and natural gas = supply ~ 90% of world’s energy

14. 3 conditions for combustion
There must be a fuel (it is the fuel that releases energy)
There must be an oxidizing agent (almost always oxygen)
The ignition temperature must be reached

15. Examples of combustion reactions
CH4 + 2O2  CO2 + 2H2O + Energy C2H5OH + 3O2  2CO2 + 3H2O + Energy
METHANE
OXIDIZING AGENT
ETHANOL
FUEL

16. 3 types of combustions
1) RAPID – In a short period of time, lots of energy is released under the form of light and heat. EX: a fire, an engine, a candle 2) SPONTANEOUS – Combustion that begins without any energy from outside source. It is unpredictable. EX: In the summer, when the ground is hot and dry, wood can catch on fire spontaneously. 3) SLOW – Some energy is released over a long period of time. The energy is less intense but lasts a long time. EX: decomposition, metal corrosion, fermentation

18. 3rd type Cellular Respiration
Chemical change in which glucose and oxygen are used to generate energy. The reaction also produces carbon dioxide and water. It is exothermic.
It is a form of SLOW combustion that happens in most of our cells to keep our body warm (37ºC) and to keep it functioning.

19. Energy allows your body to function properly!

20. 4th type Photosynthesis
Chemical change that produces glucose and oxygen from solar energy, carbon dioxide and water.
It is the opposite reaction to cellular respiration and it is endothermic.
Plants are at the basis of the food chain. They are known as: PRODUCERS.