chemistry notes- teacher (chapter 1, 2, 3)

7/31/2019 Chemistry Notes- Teacher (Chapter 1, 2, 3)

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Science Focus 10Unit 1 Energy and Matter in Chemical Change pp 2-137

In this unit we will explore: Atoms, elements and compounds

Ionic, molecular, acidic and basic compounds

Naming chemical compounds

The mole

Water

Chemical equations and reactions

Chapter 1: Atoms, Elements andCompounds pp 2-39

1.1 Working with Chemicals p 6

Aboriginal peoples have been using chemical substances

for thousands of years to preserve food, treat illness,

build tools and decorate clothing. Many of these

traditional processes are still used today.

Many chemicals, even household products, have dangerous

properties and must be handled properly. An MSDS, or

Material Safety Data Sheet, lists important information

including physical properties (ie melting and boiling

points), chemical dangers, and how to store and dispose

of the chemical. See figure 1.3 p7.

The WHMIS or Workplace Hazardous Materials

Information Systemsinforms users of the dangers of

working with specific chemicals by informative labels on


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the chemical container, MSDS paperwork and

worker training programs. See figure 1.4 p8

for examples of WHMIS symbols.

Do BLM 1-1 (MSDS).

Classifying Matter

Matter is anything that has mass and occupies space.

Mixtures can be mechanical (heterogeneous) where

the separate parts are visible or solutions

(homogeneous) where the different parts are not

visible. Pure substances include elements (such as Na or Cl)

or compounds (such as NaCl). Compounds can be

chemicallyseparated into simpler substances,

elements cannot.

See figure 1.5 p10.Do Practice Problems #1-4 p10

Do Check Your Understanding #1-3 p11

1.2 Developing Atomic Theories p12

The idea that matter is made up of

small particles is rooted in work of

scientists many centuries ago. One of

the earliest theories is credited to the theoristDemocritus (~400 BC), who stated that matter is made

up of infinite tiny, indivisible, constantly moving units.

This theory has evolved over recent history.


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Historical Models of the Atom

Model of atom Why model was

proposed

Key features Why model was

rejected or modified

The Dalton Model

Billiard Ball

Dalton: 1766-1844

See figure 1.8 p13

to account for thebehaviour of

substances when

they interact with

each other

according to the law

of conservation of

mass (when

substances react,

the total mass of

substance before

and after are thesame)

All matter is composed ofsmall indivisible particles,

called atoms, that can be

neither created nor

destroyed.

All atoms of the same

element are identical in

mass and size, but

different in mass and size

from atoms of other

elements.

Atoms exist in an otherwiseempty space and are in

constant motion, during

which they may collide to

form new combinations

(compounds).

Chemical reactions change

the way in which atoms

are grouped, but they do

not change the atoms

themselves.

contained inaccuracieregarding the relative

masses of several

atoms

could not account for

the electric nature of

matter

The Thomson model

Raison BunThomson: 1856-1940

See figure 1.11 p16

to account for the

existence of small

negative charges

(cathode ray

particles)

associated with the

atom

gas discharge tube

-see figure 1.9 p13

Thomsons

experiment seefigure 1.10 p15

All materials produce

identical cathode ray

particles, which are much

smaller than even the

smallest atom, hydrogen.

All atoms contain electrons

(small negative charges)

that are distributed

throughout a positively

charged solid.

Electrons are extremelytiny compared with the size

of an atom.


the production of

high-frequency

electromagnetic

radiation

could not explain the

existence of alpha

particles (heavy,

positive charge) for

radioactive materials


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Model of atom Why model was

proposed

Key features Why model was

rejected or modified

The Rutherford model

Solar System

Rutherford: 1871-1937

See figure 1.14 p18

to account for the

deflection and

reflection of alpha

particles from goldfoil

Rutherfords

experiment see

figure 1.12 p17

Explanation of the

experiment see

figure 1.13 p17

Isotopes see

figure 1.15 p19

At the centre of every

atom, there is a small,

positively charged nucleus.

The nucleus accounts forthe majority of the mass of

the atom.

Electrons are attracted to

the nucleus and orbit in a

cloud around the nucleus.

A third subatomic

particle, neutron, with no

charge but a mass similar to

a proton exists in the

nucleus


the emission spectra

of elements

included orbitingelectrons that should

constantly radiate

energy and therefore

collapse into the

nucleus, but the

radiation and collapse

were not observed

The Bohr Model

Bohr: 1885-1962

See figure 1.19 p20

to account for the

production of

bright-line spectra

in hot gases and

absorption spectra

in cold gases

See figures

1.17,

1.18 p20

Electrons reside within

stable energy levels

(electron shells) at fixed

radii relative to the nucleus

of the atom. Transitions of

electrons to higher energy

levels require energy.

Transitions to lower energy

levels produce

electromagnetic radiation

(light and radio waves). Each energy level has a

fixed maximum number of

electrons that can reside in

it.

could not explain the

existence of sublevel

within higher energy

levels, predicted by

the shape of the

periodic table

could not fully explain

the nature of

electrons or the

nucleus

QUARKSScientists now believe that neutrons and protons are made upof even smaller particles called quarks. They believe that

matter is made up of dozens more of these subatomic particles.


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Features of a Simplified Modern Model of the Atom

(figure 1.20 p22) a tiny, dense nucleus that is surrounded by electrons (e-)

nucleus contains protons (p+) and neutrons (no

), called nucleons(exception: H-1 nucleus contains one proton only)

nucleus accounts for most of the mass of the atom

e- exist at certain allowed energy levels

p+ carry a positive charge, e- carry a negative charge and no

carry no charge. See table 1.2 p 22.

A neutral atom always has equal numbers of e- and p+

If a nucleus were the size of a baseball, the electron orbitals

around the nucleus would take up the space of an arena!

Nuclear Notation

Elements can have 2 or more isotopes, where the number

of neutrons is different. Scientists use the following

notations to describe a specific isotope:

Silicon-29 or29

14Si top number represents the mass

= total number of protons + neutrons

bottom represents the atomic number

= total number of protons in the nucleus

These two numbers can be used to determine the number

of neutrons:

mass number atomic number = # neutrons

so with Silicon-29, the number of neutrons is 29-14=15!Do Practice Problems #5-8 p23 + #4 p24

Do Check Your Understanding #2, 3, 5 p24


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1.3 Electrons and the Formation of Compounds p25During the 1800s, a Russian chemist, Dmetri Mendeleev, examined

62 elements. He developed a table of these elements based upon

the fact that they had repeating properties. The table was called

a periodic table for this reason. He further predicted the

existence and properties of unknown elements and left spaces on

his periodic table for them.

Examine our modern periodic table on p482. It displays

the known elements in a format that follows various

patterns and trends:

Elements are arranged according to increasing

atomic number (number of protons in the nucleus)

Period horizontal row

Inner-transitional elements

top period = lanthanoids (fits in period 6)

bottom period = actinoids (fits in period 7)

Group or family vertical column, each element in a

group has similar properties

Group 1 = alkali metals (react with water)

Group 2 = alkali earth metals (react with

oxygen)

Group 17 = halogens (very reactive)

Group 18 = noble or inert gases (not reactive)

Staircase line bordered by metalloids, this linedivides metalson the left from non-metalsfound on

the right. See table 1.3 p25 to examine the

properties of metals, non-metals and metalloids.


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Patterns of electron arrangement in periods & groups

Recall that Neils Bohr inferred that electrons orbit the

nucleus of the atom in fixed energy levels, and each level

can only hold a certain maximum number of electrons.The first can hold 2 electrons, the second can hold 8, and

the third can hold 8. We can use the patterns in periodic

table to predict the number of energy levels of an

elements and the number of electrons in each energy

level. Examine figure 1.22B p26.

period number shows the number of energy levels

used in each element (eg. period 2 elements have 2energy levels)

group number describes how many electrons are

found in the valenceor outermost energy level (eg.

lithium is in group 1 and has 1 valence electron)

for groups 13 18, we use the last number to

designate the number of valence electrons (eg.

elements in group 16 have 6 valence electrons) electrons fill the first orbital before they can

occupy the second, and fill the second before they

can occupy the third

when the valence level is full, it is referred to as a

stable octetsince there are 8 electrons occupying

the orbital (unless it is the first level)

The diagram representing the element beryllium looks

like this: __2e-__ Try the diagram for fluorine:__2e-__

4p+


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Do Practice Problems #9-12 p27 and BLM 1-4.

Electron Dot Diagrams, a.k.a. Lewis Dot Diagrams

American chemist G.N. Lewis invented these structures

to visualize and track electrons during bond formation.To draw:1) write its chemical symbol

2) surround it by the number of dots that represent the

atoms valence electrons

3) if an atom has more than 4 valence electrons, the

additional electrons are shown paired with others4) note that elements in the same group will have identical

dot diagrams since they have the same number ofvalence e-

Do BLM 1-6 and then BLM 1-5.

Formation of Ions

Any atom or group of atoms that either loses or gains e-

and thus carries either a positive or negative charge iscalled an ion.

Cation - positive charge, has fewer e- than p+

- metallic atoms lose electrons, eg. Na+

- remember: cats have paws(pos)

Anion - negative charge, has more e- than p+- non-metallic atoms sometimes gain electrons

from other atoms, eg. Cl- but they can also

share electrons


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See p29 figure 1.24 and 1.25 for the 3 ways to represent

the formation of ions.

Formation of Ionic Compounds

Ions do not form by themselves. Instead, as metallic andnon-metallic atoms collide with one another, their valence

electrons interact. The metal will lose its valence

electrons (the cation) and an adjacent non-metal will gain

those electrons (becoming the anion); this is a transfer

of electrons. The two ions formed are opposite in charge

and are greatly attracted to each other, forming a very

strong ionic bond. The rearrangement of electrons allowseach ion a full valence orbital (like its nearest noble gas)

and therefore leads to a greater stability and lower

energy level for the ionic compound.

Important notes about ionic compounds:

ions arrange themselves in a regular repeating pattern

called a crystal lattice(see table salt + figure 1.28,p31)

a binary ionic compound is formed from only 2

elements.

Why does Na become Na1+ and Mg become Mg2+?

Sodium (Na) has only 1 valence electron, so when it is

lost, the resulting charge is 1+, however magnesium

(Mg) has 2 valence electrons so its ion has a charge of

2+

Do BLM 1-7 to practice isotope and ion formation


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Formation of Molecular Compounds

When non-metals react with one another, electrons areNOT transferred since both atoms tend togainelectrons

to fill their valence energy level. Instead, the valence

electrons are shared. These compounds are referred to

as molecularand the sharing of electrons forms a bond

called covalent(co= share, valent= valence shell)

Important notes about molecular compounds: a diatomic molecule is composed of only 2 atoms and

a polyatomic molecule is composed of many atoms

(see and memorizetable 1.5 p 31)

molecules do NOTform a crystal lattice shape

Do Investigation 1-A p 33 + Questions 1-6 p 35

Do Check Your Understanding #1,3,6,7 p36

Do Chapter 1 Review #2,4,5,7,10,11,12,15,16,17,19,20 p38

It is important to note that the physical and chemical

properties of a compound is different from those of the

individual elements that make up the compound.


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Chapter 2: Names, Formulas and Properties

pp 40-81

2.1 Chemical Names and Formulas p 42

The IUPAC (International Union of Pure and Applied Chemistry)

was founded in 1919 and has developed a method to name chemicals

based on their composition. The systematicname of a compound

allows you to write the chemicals formula and predict some of its

properties.

Binary Molecular Compounds

Naming Rules: see table 2.2 p 44

1st name: use the name of the element found

furthest to the left on the periodic table

2nd name: add the suffix ide to the name of the

second element (eg. oxygen becomes oxide)**attach a prefix to each name to indicate how many of each atom

is present in one molecule of the compound (see and memorize the

prefixes in table 2.1 p 43)

**note that the prefix mono is not generally used for

the first element**when hydrogen is the first element in the formula, the compound

is molecular BUTprefixes are NOTused (see p54 Hydrogen

Compounds). More later.

**memorize:diatomic elements (N2, O2, H2, F2, Cl2, Br2, I2, At2,) + P4 + S8**memorize: O3 ozone NH3 ammoniaCH4 methane CH3OH methanol C2H5OH ethanol

C6H12O6 glucose C12H22O11 - sucrose H2O2 hydrogen peroxide

Do Practice Problems p44


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Binary Ionic Compounds

Naming Rules:1st name: use the name of the metal element

2nd name: add the suffix ide to the name of

the non-metal element

**the chemical formula is the simplest whole ratioof

each type of ion in the compound and it represents the

smallest repeating unit (formula unit) within a crystal

lattice (fig 1.28 p31)**prefixes are NOTused in naming ionic compounds

Study Model Problem 1 and figure 2.3 p45


Stock System:

As you look at your periodic table, you may notice that

many transitional elements have more than one possible

ionic charge.

Study Model Problem 2 and do Practice Problems #9,10 p46

A German chemist, Alfred Stock, developed a way to

indicate which cation is in a compound. The Stock

System uses a roman numeral to indicate the charge onthe metal or cation.

Study Model Problem 3 and do Practice Problems #11,12 p47

Do BLM 2-1 (and BLM 2-5 to practice the crossover method)


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Polyatomic Ions

These ions consist of two or more different atoms joined

together by covalent bonds. As a group, the

bonded atoms have either a positive or negative

charge. See the polyatomic ion table on the back

of the periodic table, and become familiar with

the common polyatomic ions in table 2.3 p51.

Naming Rules:1st name: name the cation

2nd name: name the anion

**parentheses must be placed around the polyatomic ion

if more than one are found in a chemical formula

Study Model Problems 4,5 p51 and do Practice Problems p52

Getting to know the polyatomic ions:

Many polyatomic anions contain oxygen and those that

contain the same elements are part of a family.

Anion name # of oxygen Example Formula

Per----ate 1 more pernitrate NO4-

----ate --------------- nitrate NO3-

----ite 1 less nitrite NO2-Hypo----ite 2 less hyponitrite NO1-

Do Practice Problems 17-19 p53

Do BLM 2-3 (and Check Your Understanding p55 for practice)


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2.2 Explaining Properties of Substances p56

Physical properties observable and measurable

qualities of a substance, such as melting and boilingpoints, conductivity, appearance, state (see table 2.7

p56)

Chemical properties reactive properties of a substance

Property Ionic compound Molecular

compoundState at room temp. Solid (hard, brittle,

crystal lattice shape)

Solid, liquid or gas

Melting point High Low

Attraction between

molecules

Strong because of

opposing charges

Weak

Conductivity when

solid?

No, molecules held

rigidly in crystal

lattice shape

No

Conductivity when

dissolved in water or

melted?

Yes, crystal lattice

has broken down

= electrolyte

Sometimes, but

these compounds

tend to be

non-electrolytes

Lab safety demo

Read together and sign laboratory contract

Review lab write-up guidelines

Do Investigation 2-B p58 (use BLM 2-2) and Q #1-6 p59


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Toxic Properties

There are many chemicals found in society

today with properties that producepronounced physical and psychological

effects. Some of these chemicals are

regulated or even banned by government and

others are not. Understanding chemistry

can help people make informed decisions

about personal use of such chemicals.

Examine table 2.8 p 60 to familiarize

yourself with effects of the chemicals

ethanol and nicotine.

Do Check Your Understanding #1,3,5 p62

2.3 Properties of Acids and Bases p 63

Both acids and bases have several properties in common.

These chemicals can be both dangerous and useful.

Acidic and basic solutions are electrolytes, so they

contain freely moving ions and thus conduct electricity.See figure 2.7 p63 for examples of household acids and

bases.


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Property ACID BASEArrhenius

definition(a Swedish

chemist)

releases H+

(hydrogen ions ) ina water solution

releases OH-

(hydroxide ions) in awater solution

Formula HB(aq) ->H+(aq) + B-(aq) MOH(aq) ->M+(aq) + OH-(aq)Electrolyte? Yes Yes

Taste Sour (like lemons) Bitter (like tonic water)

Feel Will burn skin Will burn skin, but bases

feel slippery (soap)

Uses removes rust refine metal

cleaning products medical drugs

pH Less than 7 More than 7

Indicators:

Litmus

Phenolphthalein

Red

Colorless

Blue

PinkFor important acids and bases and their uses see tables 2.9 and 2.10 p64.

Notes: pH indicators are made of chemicals that changes color in

response to the concentration of hydrogen or hydroxide ions.

pH meters and probes can also be used. These instruments

measure the electrical property of the solutions, which

relates to the solutions pH. They are more precise but more

expensive.

When acids and bases react, they neutralizeeach other, or

they lose their acid and base properties. The resulting

solution is a salt dissolved into water.

Strong acids react with metals to produce hydrogen gas.

Strong acid = high conductivity, weak acid = weak

conductivity


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Naming Acids:

Name the compound as though it were an ionic compound.

Use the following rules to complete the acidic name:

If the ionic name was: The acidic name is:

1. hydrogen _______ide hydro_____ic acideg. H2S = hydrogen sulfide = hydrosulfuric acid

2. hydrogen _______ate ______ic acideg. HClO3 = hydrogen chlorate = chloric acid

3. hydrogen _______ite ______ous acideg. H2SO3 = hydrogen sulfite = sulfurous acid

Notes:

Acids are aqueoussolutions so the proper way to

write the formula of an acid is with an (aq)

subscript. H2S, hydrosulfuric acid, can also be called

aqueous hydrogen sulfide.

When trying to figure out the formula of an acid

from its name, remember that you must have enough

hydrogen ions to balance the negative charge of the

anion.

If the polyatomic ion that is part of the acid ends in

a ---COO-, the hydrogen ion bonds at this end to

become ---COOH (this is called a carboxylic acid).


Do Find Out Activity p 67 and BLM 2-6

Do Check Your Understanding #3,4,5,6,8 p71


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2.4 Why Water is Weird p 72

Water is essential to life. The cells of most living

organisms are 80-95% water, and virtually all

chemical reactions for life occur in aqueoussolutions. But water also has many other unique

properties: Occurs in all 3 states on Earth

Ice is less dense than liquid

Its melting and boiling points are

higher than similar substances (see table

2.14 p72)

It has a very high surface tension

Do Investigation 2-D p73 (use BLM 2-9 to record results) and

do Q #1-3,6 p74

A Molecular View

The above characteristics of water can be explained by

several features of water.

1. Shape bent (see figure 2.13 p75)2. O-H bonds each bond is made up of

2 electrons that are more strongly

attracted by the oxygen atom so that

it gains a slightly negative charge as

the hydrogen gains a slightly positive

charge, making it a polaror dipole

molecule.These properties encourage individual water molecules to

attract each other. The negative oxygen attracts the

positive hydrogen and forms a hydrogen bond. This kind

of bond is an intermolecularbond, one betweenmolecules


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(versus intramolecularbonds, withinmolecules, like

covalent bonds which are stronger).

The hydrogen bond explains many of waters uniqueproperties:

its melting and boiling points are high

-more energy has to be added to water in order to

break these intermolecular bonds and allow ice to

melt or water to vaporize

it takes much energy just to raise the

temperature of water-the strong attraction between water molecules

must be overcome to increase the average speed

of the water molecules and thus heat the water

it has a concave meniscus and shows capillary

action

-its polar molecules are attracted to the sides of

the container when it is solid water, it floats in liquid water

-hydrogen bonds force water molecules farther

apart as it freezes and leaves the ice less dense

than liquid water

it has a high surface tension / cohesion

-hydrogen bonds pull water molecules close

together

Do Check Your Understanding #1,2,4,6 p78

Do Chapter 2 Review #1,2,4,6,8,9,10,13,14,17,18,19,22,25

p80


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Chapter 3: Chemical Reactions pp 82-

137

3.1 Recognizing and Describing

Chemical Reactions p 84

A chemical reaction, or chemical change, has taken place

when one or more substances have changed to form

different substances. The reactants are those

substances that undergo a chemical change and the

products are the new substances formed.

Evidence of a Chemical Reaction: (see table 3.1 p84)

Odor change

Color change

Formation of a gas (bubbles)

Formation of a solid (called a precipitate)

Energy change such as:

Temperature increase or decrease Light produced

Sound produced

Electricity produced*energy changes can also accompany physical changes,

which are simply changes in state

Do BLM 3-1

Solubility and Chemical Reactions

Recall that when most ionic compounds are dissolved in

water, the cations and anions separate from each other

and move about freely. Also remember that some ionic


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compounds do not dissolve well in water. If

two ionic compounds are mixed, their free

cations and anions may react with each other

to produce new substances. If the newcompound does not dissolve in water, a precipitate is

formed, and this indicated a reaction has occurred.Do Investigation 3-A p86 (use BLM 3-3 to record)

and do Q#1-6 p87

Predicting Solubility

Table 3.2 p88 outlines which ionic compounds are solublein water and which have a low solubility. To determine

whether a compound is soluble in water or not, follow

these steps:

1. locate one of the ions found in the compound on

the top row of the chart

2. look down that column of the table to find the

second ion3. if the 2nd ion is found in the high solubility

category, the compound is soluble in water and

should be given a subscript of (aq) (aqueous)

OR

If the 2nd ion is found in the low solubility

category, the compound is NOTsoluble in water

and should be given the subscript (s) (solid)It will form a precipitate in water.

Study Model Problem 1 p 89

Do Practice Problems 1-4 p90 and BLM 3-2


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Chemical Reactions and Energy Changes

Energy changes accompany any chemical reaction.

Endothermic energy is added to startthe reaction

Eg. Photosynthesis energy from the

sun is required to start the process of

converting carbon dioxide and water into

food (glucose) and oxygen in plants

Exothermic release of energyduring the reaction

Eg. Cellular respiration

the opposite reaction of

photosynthesis, where glucose

and oxygen are converted into

carbon dioxide and useful energy

in both plants and animals

Do BLM 3-4 for reinforcement

Law of Conservation of Energy

This law states that energy can be converted from one

form into another, but the

total energy of the universe remains constant.

Energy cannot be created or destroyed.


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Energy is requiredto break chemical bonds, and energy is

releasedwhen chemical bonds are formed.

Endothermic reaction moreenergy is required to

break the bonds of the reactants than is released whenthe products bonds are formed

Exothermic reaction lessenergy is required to

break the bonds of the reactant than is released when

product bonds are formed

See figure 3.8 p 92.Do Check Your Understanding #1,3,4,5 p93

3.2 Representing Chemical Reactions p94

Closed system an exchange of energy

between the system and its surroundings

occurs, but NOTan exchange of matter

Example a terrarium- the earth?

Open system an exchange of both energy and

matter between a system and its surroundings

Example a flower pot

Isolated system exchange of neither energy normatter between a system and its surroundings

Example (theoretical) a thermos


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Law of Conservation of MassDeveloped by Antoine Lavoisier (1743-1794)

This law states that during a chemical reaction, the total

mass of the reacting substances (reactants) is always

equal to the total mass of the resulting substances

(products).

Do Investigation 3-B p 95 and Q# 1-10 p96

Writing Balanced Chemical Equations

Reaction Description: hydrogen gas reacts with oxygen

gas to produce liquid water

Word equation: hydrogen + oxygen -> water

Skeleton equation: H2(g) + O2(g) -> H2O(l)

Balanced equation: 2H2(g) + O2(g) ->2H2O(l)*shows atoms are conserved

*coefficients(numbers in front of chemical

formulas) show how many of each compound is there

(note there is 1 moleculeof oxygen gas, but 2 atomsof

oxygen)Q: how many atoms of hydrogen are reacting? ______

*subscripts(letters below and to the right of each

compound) show what state each compound is in

How the balance equations:


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1. When writing the correct skeleton

equation, check your formulas to

ensure they are correct. Include

all states of matter for eachreactant and product.

2. Balance the atom or polyatomic ion

present in the greatest number. Find the lowest

common multiple to obtain whole number

coefficients to balance.

3. Repeat step 2 to balance each remaining atom/ion.

HINTS:

O2(g) when O2(g) is present in the

reaction, balance it last

When single elements are present on

one side of the equations, balance

those elements last (ie. Na, Mg)As long as complex ions are found

intact on both sides of the equation,

treat the complex ion as one group

4. Check once again to make sure the equation is

balanced by creating a table of atoms on each side

of the equation.Study Model Problem 1-3 p99-100

Do Practice Problems 5-8 p101


Do Worksheets p2 (left side)


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3.3 Types of Chemical Reactions p103Do Find Out Activity p103 using BLM 3-5 to record.

Do the appropriate sections of BLM 3-6 as equations are

learned

1. Formation Reaction: two or more reactants combine

to form a new product

Eg. X + Y -> XY

See figure 3.15 and 3.16 p104.

2. Decomposition Reaction: one compound breaks downinto two or more simpler compounds/elements

Eg. XY -> X + Y

See figure 3.17 and 3.18 p 104.

3. Single-Replacement Reaction: one element takes

the place of another element in a compound

Eg.1. A + BX -> AX + BEg.2. AX + Y -> AY + X

*many of these reactions are between a metal and a compound

(see p105)

*sometimes the reaction is between a halogen and a halogen-

containing compound (see p105)

4. Double-Replacement Reaction: the cations of two

different compounds exchange places, forming twonew compounds

Eg. WX + YZ -> WZ + YX*many of these equations result

in a precipitate forming


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or the formation of water (p105)

5. Reactions involving Carbon Compounds:

The study of carbon-containing compounds is called

organic chemistry. A hydrocarbon is acompound that contains onlyhydrogen and

carbon atoms (eg. C2H6). These compounds are

retrieved by refining crude oil and natural gas.

Approximately 95% of these hydrocarbons are

burned as fuels in exothermic combustion

reactions to create thermal energy to warm

buildings and provide energy for transportation.

Complete Combustion: a hydrocarbon

reacts with oxygen gas (or burns) to

create carbon dioxide gas, water vapor

and thermal energy. See figure 3.20 and

3.21 p108.

Incomplete Combustion: when oxygen is in poor supply,

the products are carbon dioxide gas, water vapor, carbon

monoxide, carbon (soot) and less thermal energy than

a complete combustion reaction.

*carbon monoxide is a colorless, odorless, highly

toxic gas that, when breathed in, strongly binds to red

blood cells instead of oxygen and can lead to death

Study the Tools of Science p109 and learn the chemical tests

for hydrogen, oxygen, carbon dioxide and water



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Do the rest of your Worksheet

3.4 The Mole p116

Since atoms and many compounds are very tiny, scientists group them into an

extremely large number called a mole.

The mole:

A mole is defined as the amount of substance that contains

as many elementary entities (atoms or

compounds) as exactly 12 g of carbon-12

(the most common isotope).

One mole of a substance contains 6.022 141

99x1023 particles of that substance 6.02 x 1023 is called Avogadros number

(see Did You Know p116)

The unit mol is short for the German wordMolekulargewicht, which is literally translated to,you guessed it, molecular weight!

Atomic Molar Mass (M)

this is a weighted average of 1 mol of all thenaturally occurring isotopes of that element

it is listed on the periodic table

units are in g/mol

Molar Mass of a Compound (M)

this is the mass of 1 mol of any pure substance

units are in g/mol it is determined by using the formula for that

compound(see eg. p120)Do Practice Problems p 120

Do WS p.2,4


29/29

Review significant digits worksheet

Converting Between Mass and Moles

Scientists often convert between the mass (g) of a

sample and the number of moles (mol). The followingformula is used:

n = _m_

M

n = number of moles of substance

m = mass of substance

M = molar mass of substance

Study Model Problem 1 and 2 p121 and 122

Do Practice Problems p 122 and 123

Do BLM 3-10

The Mole and the Law of Conservation of Mass

Study the chemical reaction at the top of p124. The

coefficients explain the number of molecules and/or thenumber of molesof each substance needed for the

reaction to run. Now view table 3.5 at the bottom of the

page. Notice how molecules, moles and mass are all

related in the chemical equation. Also notice that the

mass of the reactants is always equal to the mass of the

products.

Do BLM 3-10 + rest of WorksheetDo Check Your Understanding #2-6 p125

Do Chapter 3 Review #1-5,7,9-10,12(a-

b),13(a-c),14-19

Do Unit 1 Review #1-38,39-43(a-c for each),46

chemistry notes- teacher (chapter 1, 2, 3)

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