Fireworks burst into the night sky in brilliant patterns caused by chemical reactions. The different colours that we see result from reactions between different substances within the fireworks. For example, barium compounds create green fireworks, strontium compounds create red ones, copper creates blue ones and sodium yellow. Fireworks are also launched by the chemical reaction that results from the fuse being lighted. The heat of the fuse ignites the chemicals that propel the fireworks into the sky. Dr. John Polanyi In 1986, Canadian Dr. John Polanyi won the Nobel Prize in chemistry for his work investigating the properties of chemical reactions.

A chemical reaction takes place when two or more substances combine to form new substances. Different types of chemical reactions can occur, including combination, decomposition, displacement and exchange reactions. The substances at the beginning of the reaction are called reactants.

The new materials produced by the reaction are called products.

At first it may seem that the launch of a space shuttle and the activation of air bags in a vehicle have very little in common.

In fact, both of these events require a chemical reaction to work. A chemical reaction takes place when two or more substances combine to form new substances.

A chemical change in a substance results from a chemical reaction. The chemical reaction occurring in launching a space shuttle involves almost 1 500 000 L of liquid hydrogen and 545 000 L of liquid oxygen combining to form water. During this reaction, enough energy is released to put the shuttle into orbit around Earth.

In a vehicle equipped with air bags, the chemical reaction occurs on a smaller scale, but the results are also dramatic. Air bags, packed inside the frame of a vehicle, contain the explosive chemical sodium azide NaN3(s). When the vehicle is in a collision, the sodium azide reacts and forms large volumes of nitrogen gas and sodium. The sodium quickly reacts with another compound in the air bag to make less dangerous compounds. Fifty grams of sodium azide can produce 30 L of nitrogen gas in milliseconds—a reaction that releases a burst of energy. The nitrogen gas inflates the air bags instantly, cushioning the impact of the collision for the driver and front-seat passenger.

Chemical reactions can be written as word equations which gives the names of all the reactants (separated by a "plus' sign + ) followed by an arrow which points to the names of all the products (separated by a 'plus' sign +) eg. ( iron + oxygen + water → rust ) (Iron plus oxygen plus water produces rust) A chemical change results from a chemical reaction.

Evidence that a chemical change has occurred include:

• A change of colour • The formation of an odour • The formation of a solid or a gas (bubbles) • The release or absorption of energy

The reactants potassium iodide and lead II nitrate are both clear. The chemical reaction that takes place when they are combined results in a colour change in the product.

Below are three different reactions. Identify the reactants and products for each reaction. Write out the chemical word equation and the chemical equation. Reaction 1. When hydrogen peroxide is left out in the sun, it changes to water and oxygen gas. Reaction 2. A silver spoon is exposed to air. Over time, it turns a dark brown colour.

Reaction 3. Sodium and bromine react explosively to produce sodium bromide.

Hydrogen Peroxide produces water and oxygen gas H2O2 → H2O + O2 2 H2O2 → 2 H2O + O2

Silver plus oxygen produces silver Oxide Ag + O2 → Ag2O 4 Ag + O2 → 2 Ag2O

Sodium plus bromine produce sodium bromide Na + Br2 → NaBr 2Na + Br2 → 2NaBr

H2 + O2 → H2O

H H O O

O H H H2 + O2 → 2 H2O H2 + O2 → 2 H2O 2-H 2-O 4-H 2-O 2H2 + O2 → 2 H2O 4-H 2-O 4-H 2-O

H O O H

H H

H H

H H

O O

HgO → Hg + O2 Hg O 2HgO → 2Hg + O2

2HgO → 2Hg + O2 2-Hg 2-O 2-Hg 2-O

Hg OO

Hg Hg O O Hg Hg O O

Fe + O2 → Fe2O3

Fe + O2 → 2 Fe2O3

Fe + O2 → 2 Fe2O3 4 -Fe 2O 4- Fe 6 - O 4Fe + 3O2 → 2 Fe2O3 4-Fe 6-O 4-Fe 6-O

Fe OO

Fe Fe

Fe Fe

O O O

O O O

Fe Fe

Fe Fe

O O O

O O O

Fe O

OFe O

K + Br2 → KBr

2K + Br2 → 2KBr

N2 + H2 → NH3

N2 + H2 → 2NH3 2N 2H 2N 6H

N2 + 3H2 → 2NH3 N 6H 4N 6H

S8 + O2 → SO3

S8 + O2 → 8 SO3 8S 2O 8S 24O

S8 + 12O2 → 8 SO3 8S 24O 8S 24O

H2O2 → H2O + O2

H2O2 → 2 H2O + O2 2H 2O 4H 4O

2H2O2 → 2 H2O + O2 4H 4O 4H 4O

N2 + O2 → N2O

N2 + O2 → 2 N2O 2N 2O 4N 2O

2 N2 + O2 → 2N2O 4N 2O 4N 2O

Sb + O2 → Sb4O6

4 Sb + 3 O2 → Sb4O6 4 Sb 6O 4Sb 6O

Mg + P3 → Mg3P2

Mg + P3 → 3 Mg3P2 1Mg 3P 9Mg 6P

9Mg + 2P3 → 3 Mg3P2 9Mg 6P 9Mg 6P

Mg + P3 → Mg3P2

Mg + P3 → 3 Mg3P2 1Mg 3P 9Mg 6P

9Mg + 2P3 → 3 Mg3P2 9Mg 6P 9Mg 6P

Al + FeO → Al2O3 + Fe Al + FeO → Al2O3 + Fe 1Al 1Fe 1O 2Al 3O 1Fe

2Al + 3FeO → Al2O3 + 3Fe 2Al 3Fe 3O 2Al 3O 3Fe

P4 + O2 → P2O5

P4 + O2 → 2 P2O5 4P 2O 4 P 10O

P4 + 5 O2 → 2 P2O5 4P 10O 4 P 10O

Al + O2 → Al2O3

Al + O2 → 2 Al2O3 1Al 2O 4 Al 6O

4Al + 3O2 → 2 Al2O3 4Al 6O 4Al 6O

C + H2O → CO + H2

C + H2O → CO + H2 1C 2H 1O 1C 1O 2H

A chemical change, which releases energy, is called EXOTHERMIC.

When you burn something in the presence of oxygen energy in the form of heat is given off. Heat is given off when your body metabolizes food

A chemical change, which absorbs energy, is called ENDOTHERMIC. The temperature drops in a baking soda vinegar reaction. Cold Packs absorb heat energy.

CHEMICAL CHANGES INVOLVING OXYGEN Chemical changes occur because some substances react with each other when they come into contact. Among the most common types of chemical reactions are those involving oxygen. Three examples of reactions in which oxygen reacts with other substances are:

1) Combustion 2) Corrosion 3) Cellular respiration.

Combustion is a chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy. Fire is a common example of a combustion reaction. In burning, wood reacts with oxygen to give off heat and light and produce carbon dioxide and water.

Combustion could be considered the first chemical reaction used by humans.

Today, it is still one of the most important chemical reactions we use.

This fire triangle shows the three factors that keep a fire going. If any one of them is missing, the fire will not continue burning.

Corrosion is a slow chemical change that occurs when oxygen in the air reacts with a metal.

Corrosion is a chemical reaction in which the metal is decomposed (eaten away), when it reacts with other substances in the environment. Many metals can corrode. The green roofs of the parliament buildings are an example of corrosion. The red-brown copper color is replaced with the green color because copper corrodes.

Gold does not corrode. Solid solutions of metals (alloys) resist corrosion. Corrosion protection involves protecting the metal from contact with the environment and the factors that affect the reaction rate of this chemical reaction (e.g. painting the metal)

Cellular Respiration is a chemical reaction that takes place in the cells in your body.

Identification Tests: for OXYGEN

Light a wooden splint. Blow out the flame, allowing the splint to continue glowing. Hold the glowing splint in a small amount of the unknown gas. If the splint bursts into flame, then the gas being tested is oxygen.

for HYDROGEN Light a wooden splint. Hold the glowing splint in a small amount of the unknown gas. If you hear a "pop", then the gas being tested is Hydrogen.

Identification Tests:

for CARBON DIOXIDE

If you put a burning splint into Carbon Dioxide, the flame will go out and you will know the gas is not oxygen or hydrogen, but you will not know for sure that it is Carbon Dioxide.

The test for Carbon Dioxide is not a combustion test, but rather uses a liquid called limewater (a clear colorless solution of calcium hydroxide, or slaked lime) Bubble the unknown gas through the limewater solution, or add a few drops of the limewater solution to the gas and swirl it around. If the limewater turns milky, the gas is Carbon Dioxide

The Law of Conservation of Mass

In a chemical reaction, the total mass of the reactants, is always equal to the total mass of the products.

The law ties in well with the atomic theory, which states that atoms are never created or destroyed.

In a chemical reaction the atoms and molecules are simply rearranged.

In an open system some of the mass seems to disappear, when it is in the form of a gas. This law of conservation of mass however does not apply to nuclear reactions, because there Is some loss of mass: the mass is changed into energy.

First suggested by Albert Einstein in his famous equation: E =MC2

(E Is Energy, M is Mass, C2 is a large number the square of the speed of light ) A very tiny amount of mass is equal to a very large amount of energy

The speed of a chemical reaction is called the reaction rate.

•  Temperature of the reactants affects the rate of all reactions (The higher the temperature the faster the reaction rate)

•  Surface Area of the reactants affects the reaction rate (The more surface in contact, the faster the reaction rate)

•  Concentration of the reactants affects the reaction rate. (The higher the concentration, the faster the reaction rate) •  The presence of a Catalyst affects the reaction rate (Catalysts are substances that help a reaction proceed faster).

CATALYSTS

Catalysts are substances that help a reaction proceed faster. They are present with the reactants of a reaction, but they are not consumed during the reaction.

Chemical reactions involving catalysts can be found in both living and non-living things. The most common example in living things is in your body. Many reactions, such as the breaking down of food, require a catalyst called an enzyme.

Without enzymes, many reactions would require much higher temperatures- a situation that would be deadly to the human body. Enzymes can help get rid of poisons in the body quickly. For example, one product of reactions in cells is hydrogen peroxide (H2O2). Hydrogen peroxide is poisonous. An enzyme called catalase, which is found in many different types of animal and plant cells, speeds up the breakdown of hydrogen peroxide into harmless oxygen and water.

1. What is the difference between a chemical reaction and a physical change?

In a Chemical reaction a new substance is formed. A physical change is just a change in energy levels or a change of state.

2. How are reactants different from products in a chemical reaction?

Reactants produce products

3. Describe FOUR observations you might make when a chemical change occurs.

• A change of colour • The formation of an odour • The formation of a solid or a gas (bubbles) • The release or absorption of energy

4. Chemical fire starter ignites as a result of from the following reaction:

Chemical fire starter ignites as a result of from the following reaction:

2 CH3(OH) (l) + 3 O2 (g) → 2 CO2 (g) + 4 H2O (g)

a) CH3(OH) (l) O2 (g)

a) What are the reactants

b) What are the products?

c) What could be one observation you could make to conclude a chemical reaction has occurred?

b) CO2 (g) H2O (g)

c) A gas was formed and new products

5. What is the difference between an exothermic reaction and an endothermic reaction?

A chemical change, which releases energy, is called EXOTHERMIC. A chemical change, which absorbs energy, is called ENDOTHERMIC. 6. How are the reactions in the items shown useful to humans?

Hand warmer keeps your hands warm in cold weather. A cold pack reduces swelling.

Connect Your Understanding 7. a) In what ways are combustion and corrosion similar? b) In what ways are they different?

a) They are both oxidation reactions

b) Combustion reacts much faster than corrosion

8. Write the chemical word equations and equations for the following reactions: a)  Zinc and hydrochloric acid are added together. A bubbling reaction creates

hydrogen gas and zinc chloride.

b) When sugar and sulfuric acid are combined, carbon, water, and sulfur

dioxide are formed.

c) Rust is formed when iron reacts with oxygen.

Zinc plus hydrochloric acid produces zinc chloride plus hydrogen gas

b) Sugar plus sulfuric acid produce carbon plus water plus sulfur dioxide

C12H22O11 + H2(SO4 )→ C + H2O + SO2

c) Iron plus oxygen produces iron oxide Fe + O2 → Fe2O3

4 Fe + 3O2 → 2 Fe2O3

Zn + HCl → H2 + ZnCl2 Zn + 2 HCl → H2 + ZnCl2

C12H22O11 + H2(SO4 )→ 12C + H2O + SO2

9. Rewrite the following chemical reactions into chemical equations using the appropriate chemical formulas.

a) Magnesium and sulfur combine to form magnesium sulfide.

b) When calcium is added to chlorine gas, calcium chloride is formed.

c) Water is formed when hydrogen and oxygen are combined.

a) Mg (s) + S (s) → MgS (s)

b) Ca (s) + Cl2 (g) → CaCl2 (s)

c) 2 H2 (g) + O2 (g) → 2 H2O (g)

20g + X = 45g

X = 45g – 20g

X = 25g

10.

Connect Your Understanding 11. A solid mass of 25 g is mixed with 60 g of a solution. A chemical reaction takes place and a gas is produced. The final mass of the mixture is 75 g. What was the mass of gas released?

25g + 60g = 85g 85g – 75g =10g

12. If 100g of one substance reacts with 70g of another substance, what will be the mass of the products after the reaction?

100g + 70g = 170g

13. A student adds 15g of baking soda to 10g of acetic acid in a beaker. A chemical reaction occurs and a gas is given off. After the reaction, the mass of the products remaining in the beaker is 23 g. Has mass been conserved in this reaction? Explain your answer.

Yes - 2 g of gas escaped into the atmosphere

14. What is the purpose of storing food in a cooler with ice when you go camping or on a picnic? Explain your answer in terms of rate of chemical reaction.

Cooling food will slow down the chemical process that cause food to spoil

6. Why does chewing your food make it easier to digest?

Increases the surface area

7. Why should batteries be stored in the fridge when they are not being used?

Cooling the batteries slows the chemical reaction. Batteries will last longer

Extend Your Understanding 9. The catalyst manganese IV oxide is able to increase the rate at which hydrogen peroxide decomposes into oxygen and hydrogen. The enzyme catalase is found in animal livers and can perform the same function. If the hydrogen peroxide is heated to 60°C first, the catalase doesn’t work. Why?

Catalase is an enzyme that works at body temperature.

1. What is an enzyme?

Enzymes are substances that help a reaction proceed faster.

2. Explain how an enzyme is different from other catalysts.

Enzymes are substances that help a reaction proceed faster in your body. They work at body temperature.

3. What are four factors that can affect the rate of reaction?.

• Temperature • Surface Area • Concentration • Catalysts

7. Why should batteries be stored in the fridge when they are not being used?

Cooling the batteries slows the chemical reaction. Batteries will last longer

8. For each of the following reactions, how could the rate of chemical change be increased? a) a block of wood burns slowly b) an Alka-Seltzer tablet fizzes slightly c) ice-cold hydrochloric acid reacts slowly with powdered zinc

a) Increase the concentration of oxygen.

b) Heat the solvent or crush the tablet

c) Heat the acid

Assess Your Learning Key Concept Review 1. Define a chemical reaction and give an example.

When chemicals react to form new substance – the molecules are rearranged. Wood burning

2. Create a chemical word equation using the following: reactants, products, →

Reactants → products

c) Substance melted

3. Which of the following observations would not be evidence of a chemical reaction? a) precipitate (solid) formed b) heat released c) substance melted d) colour changed

4. How does the fire triangle describe the chemical reaction called combustion?

Fuel and Air need heat to combust.

5. Define the law of conservation of mass in your own words.

The mass of the reactants is equal to the mass of the products produced

9. Does a glass of pop have a greater, smaller, or identical mass after it has sat out on the table overnight? Explain your answer.

Less mass – CO2 gas has escaped into the atmosphere

10. Is Earth a closed system or an open system? Explain your answer.

Usually a closed system because of gravity. Some space vehicles have escaped the earth’s gravity.

6. What is the difference between an open and a closed system?

A closed system does not allow reactants or products to escape

Connect Your Understanding 7. Write the following reactions as chemical word equations. a) Calcium and water combine to form calcium hydroxide and

hydrogen.

b) Hydrogen gas and sulfur are products created when hydrogen sulfide decomposes or breaks down.

c) Methane and oxygen react to produce carbon dioxide, water,

and energy.

Calcium + Water → Calcium hydroxide + hydrogen Ca + 2H2O → Ca(OH)2 + H2

Hydrogen Sulfide → Sulfur + hydrogen H2S → S + H2

Methane + Oxygen → Carbon dioxide + water + energy CH4 +2 O2 → CO2 + 2H2O

8. How can you determine if a reaction is exothermic?

Heat is released or given off

9. A reaction occurs in a closed system. The mass of the products is 25 g. What was the mass of the reactants? How do you know

25 g - Law of Conservation of Mass

1. Define the following terms a) WHMIS b) matter c) elements d) periodic table e) atomic mass f) atomic number g) ion charge h) ionic compound i) molecular compound j) exothermic k) endothermic l) law of conservation of mass

a) Workplace Hazardous Material Information System

b) Anything that has a mass and occupies space c) Pure substances made of atoms

d) Table of elements arranged by atomic numbers e) Mass of one atom – protons,electrons, neutrons f) Number of protons in an element

g) Number of electrons an element usually loses or gains

h) When a metal and non-metal combine

i) When a non-metal and non-metal combine j) A chemical reaction that releases heat

k) A chemical reaction that absorbs heat

l) Mass of the reactants = mass of the products in a chemical reaction

a) poisonous and infectious causing other toxic effects b) corrosive material c) dangerously reactive material d) flammable and combustible material e) oxidizing material f) biohazardous infectious material g) poisonous and infectious causing immediate and serious toxic effects h) compressed gas

a b c

d

e

f g

h

4. What is the difference between a physical change and a chemical change?

Hardness, Color, Melting point

Physical change is a change of energy level or state. Chemical change – a new substance is created.

3. If you had to describe an unknown green solid, what properties could you use?

To soften it and make it more malleable

Used electrons to find the nucleus

6. Why must copper be heated before it can be made into something?

7. What was Ernest Rutherford’s contribution to the understanding of the atom?

8. How are metals and non-metals organized in the periodic table?

9. What is the difference between a family and a period in the periodic table?

Metals on the left side non-metals on the right side

Family – vertical Period -horizontal

Describes whether an atom will lose or gain electrons Cross the charges as you bring them down unless 1 or same.

10. a) Explain what “ion charge” means. b) How can the ion charge be used to determine the chemical formula of compounds?

11. Name the elements in the substances below. a) LiCl(s) d) ZnO(s) b) Al2S3(s) e) Br2(g) c) AgF(s)

a) Lithium Chloride

b) Aluminum Sulfide

c) Silver Fluoride

d) Zinc Oxide

e) Bromine gas

a) BeO - Ionic

12. Which of the following compounds are ionic and which are molecular? Write the chemical formula a) beryllium oxide b) lithium phosphide c) water d) sodium fluoride e) carbon dioxide f) Copper I chloride

b) Li3P - Ionic c) H2O - Molecular

d) NaF - Ionic

e) CO2 - Molecular

f) CuCl - Ionic

1 1 0 Pb 207 82 125

20 20 21 47 47 62 92 92 146

He 2 2

Ne 10 11