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Section 5.2 Introduction to Chemicals and Safety

Introduction to Chemicals and Safety

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Safety Skills Read pages 658-660 & 176-178 and answer the following questions. What does HHPS stand for? What does WHMIS stand for? Name 5 household products that are not reactive. Why do you think we use hazardous chemicals when safer methods and materials are known? Give an example of a hazardous substance that might be found in the Kitchen Bathroom Garage garden Make a list of safety rules that should be followed in the lab. What sort of consequences should be put in place for students who do not follow the lab safety rules?

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Page 1: Introduction to Chemicals and Safety

Section 5.2 Introduction to Chemicals and Safety

Page 2: Introduction to Chemicals and Safety

Safety Skills Read pages 658-660 & 176-178 and answer the

following questions.1. What does HHPS stand for?2. What does WHMIS stand for?3. Name 5 household products that are not reactive.4. Why do you think we use hazardous chemicals when safer

methods and materials are known?5. Give an example of a hazardous substance that might be

found in the1. Kitchen2. Bathroom3. Garage4. garden

6. Make a list of safety rules that should be followed in the lab. What sort of consequences should be put in place for students who do not follow the lab safety rules?

Page 3: Introduction to Chemicals and Safety

Assignment:

Label the HHPS and WHMIS symbols. (handout)

Read and sign the Lab Safety Contract and have it signed by a parent/guardian.

Lab Safety Worksheet

Page 4: Introduction to Chemicals and Safety

HHPS (Hazardous Household Products Symbols)

Page 5: Introduction to Chemicals and Safety

WHMIS (Workplace Hazardous Materials Information System)

Page 7: Introduction to Chemicals and Safety

WHAT IS CHEMISTRY?

Chemistry Is the study of matter, its

properties, and its changes or transformations.

Matter Is anything that has mass and

takes up space. Everything around us is made up

of matter (water, sand, DNA, oxygen, etc)

Page 8: Introduction to Chemicals and Safety

States of Matter There are four states of matter. They are:

Solid (s) Liquid (l) Gas (g) Plasma

▪ does not have a definite shape or volume unless enclosed in a container▪ it may form structures such as filaments, beams and double layers▪ some common plasmas are stars and neon signs.

As you move from solid to a gas some of the atoms spread apart and the matter gains energy

Page 9: Introduction to Chemicals and Safety

Physical and Chemical Properties Song All matter has physical and chemical

properties.

1. Physical Properties of chemicals describe the way they look. Examples include: colour, shine, strength, and state. A change in the way something looks is called a physical change. These include:

Evaporation (liquid to a gas) Freezing (liquid to a solid) Sublimation (solid to a gas) Melting (solid to a liquid) Condensation (gas to a liquid)

Page 10: Introduction to Chemicals and Safety

A physical change is not permanent. It is easily reversed and does not change the chemical formula or properties of the matter.

2. Chemical Properties are the behaviors that happen when a substance changes into a new one. The change itself is called a chemical change.

Page 11: Introduction to Chemicals and Safety

Reactants are the starting materials in a reaction.

Products are the new materials made in the reaction.

ReactantsProducts

Physical & Chemical Changes Song

H2

O2

H2O

Page 12: Introduction to Chemicals and Safety

Assignment:

Complete the handout “Physical or Chemical Change?”

Page 13: Introduction to Chemicals and Safety

Physical or Chemical Changes?Change Type of Change?1. The steel wool turned the block pot shiny silver.2. Lightning flashed across the sky.3. Acid caused limestone to fizz.4. The back steps are rotting out.5. The piece of lemon turned the tea cloudy.6. Spilt gasoline dried, but left a bad odor in the room.7. The gravy in the refrigerator jelled.8. A blue-green lobster turned red as it cooked.9. A cavity appeared in a tooth.10. Flash cameras flashed after the wedding photo.

Page 14: Introduction to Chemicals and Safety

Chemicals and Chemical ChangesSection 5.1

Page 15: Introduction to Chemicals and Safety

Classifying Matter

Matter

Pure Substances

Compounds

Elements

Mixtures

Homogeneous Mixtures(Solutions)

Heterogeneous Mixtures

Page 16: Introduction to Chemicals and Safety

Definitions Pure Substances

All the particles are the same. The substance has constant properties.

A. Elements Are pure substances that are made up of only 1 type of

atom. They can be identified with a chemical symbol. Ex. Carbon = C

B. Compounds Are pure substances that contain two or more different

elements in fixed amounts. They can be written as a chemical formula. Ex. Water = H2O

Page 17: Introduction to Chemicals and Safety

Mixtures Video Clip Mixtures

Are a combination of two or more substances that are not chemically combined. They are simply in the same place at the same time.

Homogeneous Mixtures Mixtures are uniform. It’s parts are not

distinguishable. Ex. Pop, salt water.

Heterogeneous Mixtures Mixtures are not uniform. It’s parts are easily

distinguishable. Ex. Pizza, salad, sand and water.

Page 18: Introduction to Chemicals and Safety

A Chemical Reaction usually occurs when:

1. Color Change occurs2. Gas is formed (bubbles)3. Precipitate

▪ A solid that forms in a liquid4. Energy change

▪ Exothermic – heat/light is given off (feels warm)

▪ Endothermic – heat is absorbed (feels cold)

5. Very difficult to reverse

Page 19: Introduction to Chemicals and Safety

Assignment:

Read pages 172-174 and complete questions 1, 2, 4, 5 on page 175.

Complete the handout “Elements, Compounds and Mixtures”

Page 20: Introduction to Chemicals and Safety

Atoms and Elements

Page 21: Introduction to Chemicals and Safety

The Atom The atom is the smallest particle of an

element that retains the same properties of that element (Democritus, 4th century BCE).

Atoms are the basis for everything in the Universe. Everything is made of matterand all matter is made of atoms.

Page 22: Introduction to Chemicals and Safety

Dalton’s Atomic Theory John Dalton (1700) stated the following ideas:

1. All elements are composed of tiny indivisible particlescalled atoms.

2. Atoms of the same element are identical.The atoms of any one element are differentfrom those of any other element.

3. Atoms of different elements can combine witheach other in simple whole number ratios toform compounds.

4. Chemical reactions occur when atoms are separated,joined, or rearranged. However, atoms of one elementare not changed into atoms of another by a chemical reaction.

Page 23: Introduction to Chemicals and Safety

Elements and Atomic Structure

The Bohr-Rutherford model of the atoms suggests that atoms are composed of three types of subatomic particles:1. Protons: heavy, positively charged particles

found in the core of the atom called a nucleus.2. Neutrons: heavy, neutral particles found in

the nucleus.3. Electrons: light, negatively charged particles

with almost no mass that circle the nucleus at different energy levels called orbits or shells.

Particle Symbol Charge Approximate Mass

Proton p+ 1+ 1Neutron n0 0 1Electron e- 1- 1/1840

Page 24: Introduction to Chemicals and Safety

Video Clip on Atomic Structure

Page 25: Introduction to Chemicals and Safety

Atomic Structure Atomic Number is the number of protons. This number is

constant, it does not change.

Mass Number is the number of protons and neutrons. The number of neutrons can change, so the mass number is not constant.

Standard Atomic Notationfor an element shows it’s mass numberat the top, it’s chemical symboland it’s atomic number at the bottom.

Since atoms are neutral:# of electrons = # of protons.

Therefore:mass number – atomic number = # of neutrons

12C

6

Page 26: Introduction to Chemicals and Safety

Chemical Symbols Each element has a one or two letter symbol (a

few have three). The first letter is always capitalized, and the second it is always lowercase.

For many, it is the first letter or two of their name.

Some symbols came from the element’s name in Latin, so the letters don’t always match the name.• Lead = Plumbum = Pb

Page 27: Introduction to Chemicals and Safety

You are responsible for knowing the name and thesymbol for the following elements (spelling counts):

Name Name Name Name

H He Li BeB C N OF Ne Na M

gAl Si P SCl Ar K CaMn

Sb Zn Rn

Co I Br RaFe Xe Kr PbNi W Ag HgCu Pt Sn Au

Page 28: Introduction to Chemicals and Safety

Assignment:

Subatomic Particles Worksheet (handout)

Quiz on the 40 elements (names/symbols)

The Elements Song

Page 29: Introduction to Chemicals and Safety

ElementName

Atomic Number

Mass Number

StandardAtomic Notation

# of p

# of e

# of n

Aluminum40 Ar

18

4

5

40

Carbon

18

19

2

0

Subatomic Particles Worksheet (Blackline Master 3.3)

Page 30: Introduction to Chemicals and Safety

ElementName

Atomic Number

Mass Number

StandardAtomic Notation

# of p

# of e

# of n

3

12

Neon

7

8

31

19

14

16

Sodium

Page 31: Introduction to Chemicals and Safety

The Periodic TableSection 5.5The Elements Song-Animated Periodic Table

Page 32: Introduction to Chemicals and Safety

History of the Periodic Table The periodic table was first arranged

by Mendeleev according to mass number.

Mosely (1913), a student of Mendeleev, decided to try to arrange the periodic table according to atomic number. This method worked better and it is how the periodic table is arranged today.

Page 33: Introduction to Chemicals and Safety

Each element behaves in a different way from all other elements because it has different properties.

However, some behave similarly so they are grouped together and arranged in rows and columns.

Page 34: Introduction to Chemicals and Safety

Horizontal rows (across) are called periods. There are 7 of them. Elements are arranged by increasing atomic number.

A column (down) is known as a group. Elements in a family group share similar chemical properties.

Page 35: Introduction to Chemicals and Safety

Group A Elements Representative elements.

Group 1A - Alkali metals react with water to form basic or alkaline solutions.

Group 2A - Alkaline Earth Metals react with oxygen to then react with water to form alkaline solutions.

Group 7A – Halogens combine with other elements to form salts.

Groups 8A - Noble Gases or Inert Gases are chemically unreactive.

For Group A elements ONLY,if you know the group #, thenyou know the number of electronsin the outer shell or orbit.

Page 36: Introduction to Chemicals and Safety

Group B Elements

Transition elements. Found in the middle of the periodic table. The group number does not indicate the

number of electrons in the outer shell.

Page 37: Introduction to Chemicals and Safety

METALS Elements found to the

left of the “staircase” are metals. Common properties include: Shiny Conduct electricity Melt when heated Malleable (can be

beaten into thin sheets) Tend to lose electrons Ductile (can be formed

into wire)

NONMETALS

Elements found to the right of the “staircase” are nonmetals. Common properties include: Not shiny Not malleable Low melting point Poor conductor of

electricity Brittle Tend to gain electrons

Page 38: Introduction to Chemicals and Safety

Metalloids Elements found touching either side of the

staircase are called metalloids or semi-metals. Have properties of both metals and nonmetals. Common properties include:

- Solids- Can be shiny or dull- Ductile- Malleable- Conduct electricity better than nonmetals but

not as good as metals.

Page 39: Introduction to Chemicals and Safety

Assignment:

Color coding the periodic table.

Page 40: Introduction to Chemicals and Safety
Page 41: Introduction to Chemicals and Safety

Elements 43, 61, and from 84 on are all radioactive.

Elements 43, 61, and from 93 on have been made by man (synthetic).

There are 11 gases: Hydrogen, Helium, Nitrogen, Oxygen, Fluorine, Neon, Chlorine,

Argon, Krypton, Xenon, Radon

There are 2 liquids: Bromine, Mercury

Inner Transition Elements Lanthanide Series – Begins at Cerium #58 Actinide Series – Begins at Throrium #90

Blank spots on the table are for elements that have notbeen made yet.

Page 42: Introduction to Chemicals and Safety

Lanthanide SeriesActinide Series

Page 43: Introduction to Chemicals and Safety

Electron Orbits and Energy Levels

Electrons are arranged in orbits around the nucleus of the atom. The orbits are also known as energy levels.

Orbits or Energy Levels Number of Electrons/Level

1 22 83 84 185 186 32

Page 44: Introduction to Chemicals and Safety

Drawing Bohr-Rutherford Diagrams Electron orbits are filled from the

inside out. (The orbits closest to the nucleus fill first.)

Atoms are stable (do not react with other atoms) when their outermost orbit is full.

Page 45: Introduction to Chemicals and Safety

Assignment:

Complete the sheet on Bohr-Rutherford Diagrams.

Fill in the worksheet with Bohr diagrams. (We are only going to look at the first 20 elements)

When you are finished see if you can observe any patterns in the organization of the table.

Page 46: Introduction to Chemicals and Safety

BOHR-RUTHEFORD

Page 47: Introduction to Chemicals and Safety

Lewis Dot Structures Lewis Dot Structure shows only the valence

electron arrangement for each element.

Valence electrons are electrons that are in the outermost energy level only. These are the electrons that will determine the ionic charge of an atom.

To draw Lewis dot diagrams write the symbol for the element, then draw dots around the symbol to represent the number of valence electrons. Electrons are placed one on each side going around the symbol.

Page 48: Introduction to Chemicals and Safety

Lewis Dot:

Oxygen Fluorine

Page 49: Introduction to Chemicals and Safety

HOMEWORK

1. Draw the Lewis Dot Structure for the first 20 elements

2. List all elements that are stable.3. List all elements that have only 1

electron in their outer level.4. List all elements that are only 1

electron short of a full outer level.5. Look for patterns on your periodic

table.

Page 50: Introduction to Chemicals and Safety

LEWIS DOT

Page 51: Introduction to Chemicals and Safety

Isotopes Isotopes are atoms that have the same number of

protons, but different numbers of neutrons. Therefore, they also have different mass numbers and different atomic masses. Isotopes are still chemically alike because they have identical numbers of protons and electrons.

Ex. Three Isotopes of Carbon are Carbon-12, Carbon-13, and Carbon-14. Complete the table for each.Symbol 12C

6

13C 6

14C 6

# neutrons 6

#protons 6

# electrons 6

Page 52: Introduction to Chemicals and Safety

Ions Normally, atoms have no charge because the

number of protons (+) equals the number of electrons (-). When forming a compound, an atom can gain or lose 1 or more electrons.

Ion - an atom which has a positive or negative charge.

Remember - atoms want a full outer orbit, so they tend to lose or gain electrons to do this.

Page 53: Introduction to Chemicals and Safety

There are two kinds of ions:

1. Cations An atom or group of atoms with a positive charge. Compared to a neutral atom, cations have less electrons. Metals tend to lose electrons and form cations.

2. Anions An atom or group of atoms with a negative charge. Compared to a neutral atom, anions have more electrons. Nonmetals tend to gain electrons and form anions. Names of anions end in “ide”

Page 54: Introduction to Chemicals and Safety

Using the Periodic Table to Find Ionic Charges

1. Metals: groups IA (1A), IIA (2A), and IIIA (3A)

Lose electrons when they form ions. Their ionic charge is positive (cations). Their charge equals the group number.

Ex. Group 1A = 1+ Li+Group 2A = 2+ Mg2+

Group 3A = 3+ Al3+

Elements in groups 4A and 8A usually don’t form ions

Page 55: Introduction to Chemicals and Safety

2. Nonmetals: groups 5A, 6A, and 7A Gain electrons when they form ions (anions).

The charge is found by subtracting the 8 from the group number.

Ex. Group 5A = 5 - 8 = 3- N 3-

Group 6A = 6 - 8 = 2- O 2-

Group 7A = 7 - 8 = 1- F-

Page 56: Introduction to Chemicals and Safety

3. Transition Metals (Group B) These charges can’t be read from the

periodic table. These metals can have more than one charge, so a roman numeral must be used to indicate which ion is used.

Ex. Iron (II) – Fe2+ and Iron (III) – Fe3+

Lead (II) – Pb2+ and Lead (IV) – Pb4+

Page 57: Introduction to Chemicals and Safety

Ionic CompoundsSection 5.8

Page 58: Introduction to Chemicals and Safety

Ionic CompoundsBinary Ionic Compounds

Only contain two elements Two ions held together by electrical

attraction. Made of a cation (metal) and a anion

(nonmetal)

Page 59: Introduction to Chemicals and Safety

Writing Formulas for Ionic Compounds

1. Write the symbol for your metal and nonmetal

2. Write the charges for each3. Cross-over the charges from top to

bottom4. Remove the charges5. Simplify the numbers and remove

the 1’s

Page 60: Introduction to Chemicals and Safety

1. Sodium Chloride

2. Calcium Oxide

3. Calcium Phosphide

4. Mercury (II) Nitride

Page 61: Introduction to Chemicals and Safety

Naming Ionic Compounds1. Name the cation first!

2. Figure out if you need a Roman Numeral next to the cation (Group B Metal)

3. Name the anion (ending in the suffix “ide”)

Page 62: Introduction to Chemicals and Safety

Formula NameLiF Lithium FlourideNaClCaCl2Al2O3

CuBr2

Page 63: Introduction to Chemicals and Safety

Polyatomic IonsSection 5.9

Page 64: Introduction to Chemicals and Safety

Polyatomic Compounds Ternary Ionic Compounds

Contain three or more elements Joined by an electrical attraction Pure substances that join:

1. A metal with a polyatomic ion2. A polyatomic ion with a nonmetal3. Two polyatomic ions

Polyatomic ions Groups of atoms that stay together and

carry an overall charge

Page 65: Introduction to Chemicals and Safety

Common Polyatomic Ions and their Charges

Polyatomic Ion

Formula Charge

Hydroxide OH 1-Nitrate NO3 1-Chlorate ClO3 1-Bicarbonate HCO3 1-Carbonate CO3 2-Sulfate SO4 2-Phosphate PO4 3-Ammonium NH4 1+Fluorate FO3 1-Iodate IO3 1-Bromate BrO3 1-

Page 66: Introduction to Chemicals and Safety

Writing Polyatomic Formulas

Following the same rules as for Ionic Compounds we….

1. Write the symbol for your metal and polyatomic ion

2. Write the charges for each3. Cross-over the charges from top to bottom

(if needed)4. Remove the charges5. Simplify the numbers and remove the 1’s

When you are adding a subscript to a polyatomic ion you must put brackets around it.

Page 67: Introduction to Chemicals and Safety

1. Lithium nitrate

2. Sodium sulfate

3. Calcium carbonate

4. Ammonium chlorate

5. Aluminum hydroxide

Page 68: Introduction to Chemicals and Safety

Naming Polyatomic Compounds1. Name the cation and the

polyatomic ion Cation is always named first!

2. Figure out if you need a Roman Numeral in the name

3. Which Roman Numeral4. Check your work

Page 69: Introduction to Chemicals and Safety

Formula NameK2CO3

Na2SO4

AgNO3

Ni2(CO3)3

Page 70: Introduction to Chemicals and Safety

Comparing Ionic CompoundsIonic Compounds Formulas

2 elements(metal + nonmetal)

Names Name always has

an–ide ending

Polyatomic Compounds Formulas

3 or more elements(Metal + polyatomic ion)

If there are brackets it is automatically a polyatomic compound

Names Name always has an –ate or –ite ending

EXCEPTIONSOH – hydroxideCN - cyanide

Page 71: Introduction to Chemicals and Safety

Molecular CompoundsSection 5.10

Page 72: Introduction to Chemicals and Safety

Molecular Compounds Molecular

Compounds Made of two nonmetals

and have no charge. Formed using covalent

bonds.

Covalent Bonds Shared pairs of electrons

between two nonmetal elements that hold the atom together.

Page 73: Introduction to Chemicals and Safety

Diatomic Elements If these elements are

alone they pair up with another of their kind.

They are written with the subscript 2 (H2)

Share electrons in a covalent bond instead of existing alone by themselves.

These elements are known as the Magic 7 (they make the shape of a 7 on the periodic table…except for H)

I Have No Bright Or Clever Friends.

I2, H2, N2, Br2, O2, Cl2, F2

Page 74: Introduction to Chemicals and Safety

Naming Molecular Compounds1. The first element in the name is named

using the full name2. The second element is named using the

ending –ide.3. Prefixes are used for each element to

indicate the number of atoms present.4. The prefix –mono is only used to name

the second element CO = Carbon monoxide NOT

Monocarbon monoxide.

Page 75: Introduction to Chemicals and Safety

Prefixes in Molecular Compounds

Prefix Number ExampleMono- 1 Carbon monoxide CODi- 2 Carbon dioxide CO2Tri- 3 Sulfur trioxide SO3Tetra- 4 Carbon tetrafluoride CF4Penta- 5 Phosphorus

pentabromidePBr5

Hexa- 6 Sulfur hexafluoride SF6Hepta- 7 Dichlorine heptoxide Cl2O7Octa- 8 Trichlorine octoxide Cl3O8Nona- 9 Nonaphosphorus

dichlorideP9Cl2

Deca- 10 Tetraphosphorus decoxide

P4O10

Page 76: Introduction to Chemicals and Safety

Many molecular compounds have both common names and scientific names.Common

NameScientific Name

Water Dihydrogen monoxide

H2O

Ammonia Nitrogen trihydride NH3

Ozone Trioxide O3

Page 77: Introduction to Chemicals and Safety

Writing Formulas for Molecular Compounds

1. Write the symbol for each element2. Write the subscript from the prefix

(no criss cross)

Do not write 1’s.

Do not reduce any numbers.

Page 78: Introduction to Chemicals and Safety

Try the Following:

Dinitrogen tetrahydride

Heptafluorine hexoxide

Se8Cl3

S9I

Page 79: Introduction to Chemicals and Safety

Characteristics of Ionic and Molecular CompoundsIonic Compounds

High melting and boiling points

Usually solid at room temperature

Will dissolve in water Conduct electricity Atoms held together by

strong bonds Made of metals and

nonmetals Examples:

NaCl, AgI, Fe2O3

Molecular Compounds

Low melting and boiling points

Many are gases at room temperature

Will not dissolve in water, but can dissolve in non-aqueous solutions (don’t contain H2O)

Cannot conduct electricity Weak bonds between

molecules Made of nonmetals Examples:

H2O, CO2, CI2

Page 80: Introduction to Chemicals and Safety

Naming Compounds Review

What is it made of?

2 elements (metal + nonmetal)

Name the metalName the nonmetal

(“ide” ending)

Do you need Roman Numerals?

3 or more elements

Name the metalName the polyatomic

ion (“ate or “ite” ending)

Do you need Roman Numerals?

2 elements(nonmetals)

Put prefixes in front of the names to tell how many atoms there are.*No Mono in the first

name

The second name ends in “ide”

Page 81: Introduction to Chemicals and Safety

Writing Formulas Review

What is it made of?

2 elements (metal + nonmetal)

“ide” ending

1. Write the symbols2. Write the Charges3. Cross the Charges4. Remove the Charges5. Reduce and Remove 1’s

3 or more elements“ate or ite” ending

1. Write the symbols2. Write the Charges3. Cross the Charges4. Remove the Charges5. Reduce and Remove 1’s*Brackets if necessary

2 elements(nonmetals)“ide” ending

1. Write the symbol2. Write the subscript for the prefix.3. Repeat for the next element.

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Word EquationsSection 6.1

Page 83: Introduction to Chemicals and Safety

Word Equations A word equation is one way of representing a

chemical reaction. It tells you what reacts and what is produced. Word equations are written like this:

Reactants -> Products

When hot steel wool (iron) is put into a bottle of oxygen, there is a spectacular reaction and iron (III) oxide is produced. The word equation would be:

Iron + Oxygen -> Iron (III) oxide

Page 84: Introduction to Chemicals and Safety

Try These…

Write the word equations for each of the following examples:

1. A coil of copper wire is placed in a glass of colorless silver nitrate solution. Silver ions form on the coil, and the solution turns into copper (II) nitrate (which is blue).

2. Hydrogen and zinc chloride are produced when zinc is added to hydrochloric acid.

Page 85: Introduction to Chemicals and Safety

Assignment

Do questions 1, 2, 3 & 4 on page 219

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Conserving MassSection 6.3

Page 87: Introduction to Chemicals and Safety

Conserving Mass The Law of Conservation of Mass states that in a

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

Example 1:Methane + oxygen -> water + carbon dioxide

The mass of the methane and the oxygen combined should equal the mass of the water and the carbon dioxide.

If methane = 20g, oxygen = 30 g, and water = 40g what is the mass of the carbon dioxide?

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Example 2:Solution A has a mass of 50g. Solution B has a mass of 30g. When they are mixed together a chemical reaction occurs and a gas and a liquid are produced. If the mass of the final liquid is 60g, then how much gas was produced?

Page 90: Introduction to Chemicals and Safety

Assignment

Do questions 1-5 on page 223.

Page 91: Introduction to Chemicals and Safety

Counting Atoms 1. Subscripts

C N2

2. Coefficients 3C 2N2H4

3. Brackets Al2(SO4)3 3Ca3(PO4)2

Page 92: Introduction to Chemicals and Safety

Complete the examples below:Type of Atom

# of Atoms Type of Atom

# of AtomsCaF2 NH4NO3

Type of Atom

# of Atoms Type of Atom

# of Atoms

2CaF2

3Be(OH)2

Page 93: Introduction to Chemicals and Safety

Balancing Chemical EquationsSection 6.5

Page 94: Introduction to Chemicals and Safety

Skeleton Equations A skeleton equation represents all chemicals by

their formulas. It is NOT balanced. Skeleton equations and chemical equations are universal. They can be understood in every language all over the world!

Word Equation:

Methane + oxygen -> water + carbon dioxide

Skeleton Equation:

CH4 + O2 -> H2O + CO2

Page 95: Introduction to Chemicals and Safety

Skeleton Equations A skeleton equation is NOT balanced. These

equations are universal and can be understood all over the world!

Word Equation:

Methane + oxygen -> water + carbon dioxide

Skeleton Equation:

CH4 + O2 -> H2O + CO2

Page 96: Introduction to Chemicals and Safety

Balanced Chemical Equations In a balanced chemical equation

the reactants and the products are equal in the number of atoms. (This follows the Law of Conservation of Mass)

Page 97: Introduction to Chemicals and Safety

Rules:1. Begin balancing with the most complicated-looking group.

A polyatomic ion, or the group that has the most elements and numbers in it.

2. Lock this in with a coefficient of 1 and balance any uneven elements.3. Save any single elements in the reactant and products for

last. Especially if it is hydrogen or oxygen.

4. If you get stuck, double the most complicated-looking group and try again. 5. Make sure that all coefficients are in the lowest-possible ratio.

Know when to quit! None of the reactions you will encounter will be that difficult. If the coefficients are getting wild, double-check what you’ve done since you may have a simple mistake.

Page 98: Introduction to Chemicals and Safety

Rules:1. Begin balancing with the most complicated-looking group.

A polyatomic ion, or the group that has the most elements and numbers in it.

2. Lock this in with a coefficient of 1 and balance any uneven elements.3. Save any single elements in the reactant and products for

last. Especially if it is hydrogen or oxygen.

4. If you get stuck, double the most complicated-looking group

and try again. 5. Make sure that all coefficients are in the lowest-possible

ratio.

Page 99: Introduction to Chemicals and Safety

Balancing Examples

H2 + N2 -> NH3

Type of Atom

Reactants Products

HN

Page 100: Introduction to Chemicals and Safety

Balancing Examples

NaCl + BeF2 -> NaF + BeCl2

Type of Atom

Reactants Products

NaBeClF

Page 101: Introduction to Chemicals and Safety

Balancing Examples

K2O + H2O -> KOH

K2O + HOH -> KOHType of

AtomReactants Products

KOH

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Balancing Examples

FeCl3 + Be3(PO4)2 -> BeCl2 + FePO4

Type of Atom

Reactants Products

FeBeCl

PO4

Page 103: Introduction to Chemicals and Safety

Try These:

1. Mg + HNO3 -> H2 + Mg(NO3)2

2. Zn + HCl -> ZnCl2 + H2

3. Al + Fe3N2 -> AlN + Fe4. Fe + O2 ->   Fe2O3

5. KClO3 ->   KCl +   O2

6. O2 + C6H12O6 -> H2O +   CO2

7. S8 + F2 ->   SF6

Page 104: Introduction to Chemicals and Safety

Assignment:

Practice sheet balancing equations.

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Types of ReactionsSection 6.6

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There are five main categories of chemical reactions:

1. Combustion2. Synthesis3. Decomposition4. Single Displacement5. Double Displacement

Page 107: Introduction to Chemicals and Safety

Combustion Combustion is the very

rapid reaction of a substance with oxygen to produce compounds called oxides (CO2 and H2O). We often call this process burning.

The fuel can be a variety of things but it is often a hydrocarbon such as gasoline, natural gas, kerosene, or candles.

Page 108: Introduction to Chemicals and Safety

Complete Combustion The formula for combustion of a hydrocarbon is:

CX HX + O2 -> CO2 + H2O + energy

When you light a lighter the following reaction occurs:Butane + oxygen -> carbon + water + energy

dioxide

2C4H10 + 13O2 -> 8CO2 + 10H2O + energy

Page 109: Introduction to Chemicals and Safety

Incomplete Combustion Incomplete combustion occurs when

there is not enough oxygen. The formula is:

CXHX + O2 -> CO2 + CO + C + H2O + energy

Carbon monoxide is an odourless, colourless gas that is extremely poisonous. It blocks the bodies ability to use oxygen, suffocating it and causing death.

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Synthesis and DecompositionSection 6.7

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Synthesis Synthesis Reactions involve the combination of

smaller atoms or compounds into larger compounds. They are also known as combination reactions. They have the following general formula:

A + B ➜ AB

If both reactants are element, then the reaction MUST be synthesis.

Eg. A B AB2H2 + O2 ➜ 2H2O

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Synthesis reactions sometimes involve joining two compounds into a larger one.

Eg.Hydrogen + ammonia ➜

ammonia chloride chloride

HCl + NH3 ➜ NH4Cl

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Decomposition Decomposition Reactions involve the splitting

of a large compound into smaller molecules or elements. They have the following general formula:

AB ➜ A + B

If there is only 1 reactant, then the reaction MUST be decomposition.

Eg. AB A B2H2O ➜ 2H2 + O2

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Single and Double ReplacementSection 6.9

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Single Replacement/Displacement

Single Displacement - The reactants MUST be an element and a compound. The general formula is:

A + BC ➜ B + AC

Single displacement can involve metals:

Eg. Na + KCl ➜ K + NaCl

Single displacement can involve nonmetals:

Eg. F2 + LiCl ➜ LiF + Cl2

Remember: If the single element is a metal it will replace the metal.If the single element is a nonmetal it will replace the nonmetal.

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Double Replacement/Displacement

Double Displacement - The reactants are two compounds. Two elements replace one another to create new products.

AB + CD ➜ AD + CB

Eg.

NaOH + FeCl3 ➜ Fe(OH)3 + NaCl

When you write the two new compounds formed, you must cross charges to get the correct new formulas.

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synthesis

Page 118: Introduction to Chemicals and Safety

Reaction Types Review:Questions to Ask:

One Reactant?

Two Elements?

A Hydrocarbon and oxygen?

An Element and a compound?

Two Compounds

Types of Reaction

Decomposition

Synthesis

Combustion

Single Displaceme

nt

Double Displaceme

nt

Yes

Yes

Yes

Yes

Yes

No

No

No

No

Page 119: Introduction to Chemicals and Safety

HydrocarbonsSection 5.12

Page 120: Introduction to Chemicals and Safety

Organic compounds are molecular substances that contain carbon and hydrogen atoms as building blocks. Methane is the simplest organic compound (CH4) and there are tens of thousands of others.

Carbon is the element that is most commonly found in molecules. That is because of it’s great combining capacity. Carbon has four lone valence electrons so it would like to bond or share with 4 other atoms. This is the maximum number of bonds a single atom can make!

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Most foods, and most of our bodies, are made up of organic compounds. The two main sources of organic compounds are:1. The ones that plants produce during photosynthesis

including sugars, carbohydrates, and fats.2. Fossil fuels found underground that were made millions

of years ago from decaying plant and animal material.

Hydrocarbons are compounds with only hydrogen and carbon in them. They are also known as fossil fuels. (Methane - CH4 , butane - C4H10 , propane - C5H12)

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Synthetic SubstancesSection 5.13

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Chemical Wizardry: Synthetic Substances

Natural products are obtained from natural sources like animals, plants, and minerals. Leather, wool, and cotton are examples.

Synthetic products are made by man. Lycra, kevlar, and vulcanized rubber are just a few examples.

Polymers are long thin molecules formed from smaller molecules linked together. They have very different properties than the molecules they are formed from. There are natural and artificial polymers. Plastics are made from polymers and so are starches found in potatoes.

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Acids and BasesSection 8.2 & 8.3

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Acids and bases are molecular compounds that break into ions in water.

An acid: - tastes sour- reacts with some metals to produce hydrogen gas- is a good conductor of electricity- reacts with a base to produce salt and water

Common acids include:Common Name Found invinegar (acetic acid) salad dressingcitric acid oranges and lemonsascorbic acid vitamin Clactic acid sour milkcarbonic acid carbonated drinks, popacetylsalicylic acid aspirinsulfuric acid car batterieshydrochloric acid your stomach for

digestion

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A base: - tastes bitter- feels slippery- is a good conductor of electricity- reacts with an acid to produce salt

and water

Common bases include:Common Name Found in

sodium hydroxide drain cleaner

potassium hydroxide soap, cosmetics

aluminum hydroxide antacids (Tums)

ammonium hydroxide window cleaner

sodium bicarbonate baking soda

potassium sulfite food preservatives

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Bases react with proteins to break them into smaller molecules. A hair clogged drain may be cleared by treating it with a drain cleaner that contains sodium hydroxide.

Indicators are substances that turn different colours to indicate the presence of acids or bases. Litmus paper is one example of an indicator. Phenolphthalein is another popular indicator.

Chemists use the pH scale to represent how acidic or basic a solution is. It was developed in 1909 to allow scientists to compare the hydrogen ion concentration in various solutions. (pH stands for percent Hydrogen) The scale goes from 1 to 14. Most acids and bases can be ranked on this scale.

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pH 1.0 Highly AcidicpH 1.5 stomach acidpH 2.0 lemonspH 3.0 applespH 5.6 normal rainpH 6.5 milkpH 7.0 NeutralpH 8.2 baking sodapH 10.0 milk of

magnesiapH 12.4 bleachpH 13.5 drain cleanerpH 14.0 Highly Basic

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http://www.brainpopjr.com/science/matter/solidsliquidsandgases/grownups.weml

http://science.pppst.com/matter.html http://www.chem4kids.com/files/matter_states.html

http://images.google.ca/imgres?imgurl=http://www.designsuperhighway.com/Flash/thumbnails/labsafety.jpg&imgrefurl=http://www.designsuperhighway.com/Flash/labsafety.html&usg=___ai-qbmKGozRRmi4VFyI5RtILpA=&h=200&w=200&sz=66&hl=en&start=73&tbnid=0vom6O-8Y8V5aM:&tbnh=104&tbnw=104&prev=/images%3Fq%3DChemistry%2Blab%2Bsafety%26gbv%3D2%26ndsp%3D18%26hl%3Den%26safe%3Dactive%26sa%3DN%26start%3D72

http://listverse.com/2008/03/04/top-10-amazing-chemical-reactions/

http://www.nclark.net/ChemicalReactions