Question of the Day Rules You must work alone You may use your textbook today You have 5 minutes to complete the QOD Good luck!!

Questions of the Day A coalition was formed recently to protest the use of dihydrogen monoxide. According to the coalition, the widespread use of this substance has harmful effects on human health and the environment. 1)What is the chemical formula for dihydrogen monoxide? 2)Dihydrogen monoxide is the main component of acid rain. Is it the solute or the solvent? Explain your answer.

1) What is the chemical formula for dihydrogen monoxide? Answer: H2OH2O

2) Dihydrogen monoxide is the main component of acid rain. Is it the solute or the solvent? Explain your answer. Answer: It is the solvent because it represents the greater part of the solution.

What are we doing Today? QOD Make sure A-B Lab is handed in Types of Chemical Changes (Ch.4) Dates of Tests & Labs Class Work Get back Ch. 3 (ST) Test

Dates of Tests/Labs Ch. 3 EST Test, Monday, November 24 Tutorial Thursday, November 20 after school Lab 31 Endothermic/Exothermic Wed, Nov 26 Ch. 4 ST Test, Wednesday, December 3 Tutorial Monday, December 1 after school

Types of Chemical Change (ST) We are going to learn about: 1)Acid-base Neutralization 2)Combustion 3)Cellular Respiration 4)Photosynthesis

Indicators of chemical reactions Formation of a gas Emission of light or heat Formation of a precipitate Color change Emission of odor

Acid-Base Neutralization When a strong acid and a strong base solution are mixed, a neutralization reaction occurs. In the products, a neutral salt and water are formed. (p.119)

Acid/Base Reaction Always in aqueous solution Acid (H + ) + Base (OH - ) → Salt + H 2 O NaOH + HCl → NaCl + H 2 O NH 4 OH + H 2 SO 4 → (NH 4 ) 2 SO 4 + H 2 O

2. Combustion Combustion or burning is a chemical reaction in which a fuel combines with oxygen, releasing heat. (p.121) chemicalfueloxygen heat

More commonly known as burning 1. Combustion Reactions Easily identified (release of heat) Heat Fuel For combustion 3 things need to be present: Oxygen

2) Combustion continued Three conditions must be done for combustion reaction to happen. 1)Must Have Fuel 2)Must have an oxidizing agent (example: oxygen) 3)Ignition temperature (must have a minimum temperature to start combustion)

Fire Triangle

Combustion A reaction in which a compound (often carbon) reacts with oxygen CH 4 + O 2  CO 2 + H 2 O

1. Combustion Reactions Sulphur (in gasoline): S (s) + O 2(g) SO 2(g) + Heat 2 H 2(l) + O 2(l) 2 H 2 O (g) + Heat Rocket Fuel:

The charcoal used in a grill is basically carbon. The carbon reacts with oxygen to yield carbon dioxide. The chemical equation for this reaction is C + O 2  CO 2

Typed of Combustion 1) Rapid: a large amount of heat &light are produced in a short time Ex. burning of matchstick 2) Spontaneous: occurs on its own,without the application of heat Ex. Forest fire, 3) Slow Combustion: over long period of time. Released gradually into the environment Ex. Cellular Respiration

What is Cellular Respiration?

C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + energy Process by which all organisms release energy stored in organic molecules

Photosynthesis is the opposite reaction to cellular respiration (which we just looked at)!

Synthesis Rxns (EST) Also called combination reactions 2 elements, or compounds combine to make one compound. A + B  AB Na (s) + Cl 2 (g)  NaCl (s) SO 3 (s) + H 2 O (l)  H 2 SO 4 (s) We can predict the products if they are two elements. Mg (s) + N 2 (g)  Mg 3 N 2 (s)

A simulation of the reaction: 2H 2 + O 2  2H 2 O

Decomposition Rxns (EST) decompose = fall apart one compound (reactant) falls apart into two or more elements or compounds. Usually requires energy AB  A + B NaCl  Na + Cl 2

Precipitation reactions (EST) An insoluble solid that forms during an aqueous reaction is called a precipitate. The calcium hydroxide reacts with carbon dioxide to form calcium carbonate, which is insoluble in water: calcium hydroxide Ca(OH) 2 + carbon dioxide calcium carbonate + water + CO 2 CaCO 3 + H2OH2O Read p.118 Precipitation and look at the table

Oxidation (EST) It is a chemical change involving oxygen or a substance with properties similar to those of oxygen.

Classwork to do: p. 134 of textbook Questions: 17, 18, 19, 20, 21, 22, 23