unit b: matter and chemical change

November 30, 2011

Unit B: Matter and Chemical Change

Corn Syrop w/Food Colouring

Baking Soda

Water

Investigation

1. Create a density tower more or less following the instructions on page 91 with the following exceptions:

- use a graduated cylinder not a 250 mL beaker- use only 15 mL of syrup, water, and oil and only 5 mL of baking soda

2. Be very careful & gentle so as not to mix each layer. When adding the water, tip the beaker and allow it to run down one side.

3. Add a few drops of coloured vinegar to: a) the oil layer. Record observationsb) the water layer. Record observationsc) the syrup layer. Record observations

Oil

November 30, 2011

1.1 Safety in the Science Class

Symbols are used to indicate how dangerous a substance is:

Caution Warning Danger


The symbols can be combined with pictures to indicate the type of danger (p.94)

Warning:Flammable

Caution:Explosive

Warning:Toxic

Danger:Irritant

Caution:Corrosive

Danger:Electrical

Warning:Biohazard

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WHIMIS (Workplace Hazardous Materials Information System) has a slightly different set of symbols:

By law, all workplaces, schools, etc require MSDS sheets for all

chemicals stored and used there. MSDS sheets use

WHMIS symbols


Examine the picture on page 93. In pairs or small groups, identify as many safety concerns as possible.

For each concern, suggest a possible solution.

Review Safety Consideration on page 95

Lego LabSafety Rap

Other: - Goggle Sanitation & Storage- Prep Room Tour

- MSDS Binder- Eye Wash Station- Broken Glass

- Fire Evacuation / Lockdown

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1.2 Organizing Matter

Matter: Anything that has mass and occupies space. Matter occurs in three different states:

Can you correctly namethe physical changes thatthese arrows represent?


All matter has both physical and chemical properties.- Physical properties describes a substance's characteristics when by itself- Chemical properties describe how a substance reacts with other substances

Physical PropertiesColourLustreMelting & Boiling PointsHardnessMalleabilityDuctilityCrystal ShapeSolubilityDensityConductivity

Chemical PropertiesReaction with acidsReaction with basesBehaviour in airAbility to burnReaction to heat

What are physical & chemical properties of gold?

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p.96 #2, 3, 5, 6p.104 #6, 7


All matter can be classified as either "pure" or as a mixture

Pure

Elements

Mixtures

CompoundsBasic building blocks, have their own symbol, listed in periodic table.

Ex. C, H, O, N

Two or more elements that are combined chemically.

Ex. H2O, CO2

Mechanical

Solutions Suspensions

ColloidsMore than one substance is visible

Ex. potting soil, salsa

One or more compounds dissolved in another - appears to be one substance

Ex. coffee, vinegar

A cloudy mixture that can be separated out or form sediments

Ex. muddy water, paint, tomato juice

Similar to a suspension, but microscopic (don't sediment, hard to separated)

Ex. Milk

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Pure Mixtures

Elements Compounds Mechanical Solutions Suspensions Colloids

algae-filledwater

salt water

sterling silver(copper dissolved in silver)

LimestoneCaCO3

oxygen(O2)


p.104 #3-5, 8, 9

November 30, 2011

1.3 Observing Changes in Matter

Changes in matter can by either physical or chemical:

A physical change is when matter changes from one state to another (ex. ice to water)

A chemical change is when two or more materials react to produce new materials (ex. H20 + CO2 --> C6H12O6 + O2


Evidence of Chemical Change:

1. Change in colour

2. Change in odour

3. Formation of a solid or gas

4. Release or Absorption of Heat Energy

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You decide... which of the following demonstrations show a physical reaction and which are chemical reactions?

Homework: p.109 #1-7

2.1 Evolving Theories of Matter

Create a time line that shows the key ideas in this chapter (p.113-120)

Start at 8000 B.C.

Point form is fine

Sketch atomic models that developed after 1800

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Chem

ists

can

sta

rt a

nd c

ontr

ol f

ire

Met

als

had

not

been

dis

cove

red.

8000 B.C. 6000 B.C.

Gold

Dis

cove

red

4000 B.C. 2000 B.C.

Copp

er D

isco

vere

d

Silv

er D

isco

vere

d

Lead

Dis

cove

red

Tin

Dis

cove

red

(can

now

mak

e br

onze

wit

h Ti

n &

Copp

er

Iron

Dis

cove

red

Mer

cury

Dis

cove

red

Stone Age Iron Age


400 B.C. 350 B.C. 1597 A.D. 1660 A.D.0

Democritus Aristotle Alchemy Boyle

Atomos = indivisible Alchemy: Only a "pseudo-science"

- Focused on turning metals into gold- not interested in understanding nature of matter- made some contributions to science

Robert Boyle, a devoted scientist, believed the purpose of chemistry was to determine the types of particles making up each substance

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1780 1808 1908 19221897Lavoisier Dalton Thomson Rutherford Bohr


Homework: Page 121 #3, 7, 8, 10

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2.2 Organizing the Elements

Read pages 122-125 and answer questions p.125 #1-7

2.3 The Periodic Table Today

InteractiveP Table

What kind of basic information about the elements can be found in most periodic tables?

November 30, 2011

2.3 The Periodic Table TodayInteractiveP TableA. Element Symbol & Name

- symbol usually first letter of latin or english name- sometimes named after location or scientist

Using your periodic table, find the symbols and names of the following elements:

Name Symbol

Calcium

Fluorine

Gold

Curium

P

Fe

K

2.3 The Periodic Table Today InteractiveP Table

B. Atomic Number- The number in the upper left is the atomic number and it represents the number of protons (+ charge)

- Because atoms are neutral, the number of protons (+) equals the number of electrons (- charge)

Using your periodic table, complete the following table:Name Number of Electrons

Copper (Cu)

Tin (Sn)

12

Ne

Lead (Pb)

Number of Protons

94

25

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2.3 The Periodic Table TodayInteractiveP TableC. Atomic Mass

- The mass of an atom is made up of the mass of protons + the mass of neutrons (electrons have very little mass)

- Atoms of the same element can sometimes have different numbers of neutrons. These are called isotopes.

- The mass number is equal to the number of protons + neutrons (not shown on periodic table)

- The number shown on the periodic table is the average of all isotopes and is called the atomic mass unit or average atomic mass

Mass Number:

2.3 The Periodic Table TodayInteractiveP TableC. Atomic Mass

Name # of Neutrons

Carbon (C) 6 12 6 6

# of ProtonsAtomic Number Mass Number

Carbon (C) 13

Carbon (C) 14

Vanadium (V) 51

Nickel (Ni) 58

Finish the table with 2 or 3 elements from the list at the bottom of page 129

November 30, 2011

2.3 The Periodic Table TodayInteractiveP TableD. Chemical & Physical Properties

Metals: Shiny, malleable, ductile, conduct electricity

Non-Metals: Solid or gas, dull, brittle, insulators which mean they do not conduct electricity (except carbon)

Metalloids: Metallic and non-metallic properties

2.3 The Periodic Table TodayInteractiveP TableD. Chemical & Physical Properties

- The periodic table is divided into groups (columns) and periods (rows)

11

3 4 5...

1234567

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InteractiveP TableD. Chemical & Physical Properties

- The groups have similar properties:

Group 1: Alkali Metals: most reactive, react when exposed to air or water. Reactivity increase as you move down the group (as the period increases.)

Who's ready to blow something up?

Group 2: Alkaline-earth Metals: less reactive than alkali metals

Group 17: Halogens: most reactive non-metals and are easily combined with other elements

Group 18: Noble Gases: most unreactive elements

MetalsMovie


InteractiveP Table

Homework: page 134

# 1-7, 9

November 30, 2011

3.1 Naming Chemical Compounds

Boot

Chaps

Elk

Fanny

Homely

Kebab

What do these words mean?


Nomenclature is the science of naming chemical compounds.

Chemical compounds can be referred to by their common name(s), their scientific name, or by their chemical formula.

Common Name(s) Scientific Name Chemical Formula

Salt Sodium Chloride NaCl

Water Dihydrogen Monoxide H2O

Hydrochloric Acid Hydrogen chloride HClMuriatic Acid

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When writing the chemical formulas:- subscript numbers indicate the number of atoms of each element (if more than one)- Italicized and subscript (s), (g), (l) are used to show state

Compound Elements # of Atoms Statein Compound in each Element

CaO(s)

CaCl2(s)

Al2O3(s)

CH4(g)

KCl(s)

Mg3(BO3)2(s)



November 30, 2011

3.2 Ionic Compounds

An ion is an atom that has become electrically charged due to the gain or loss of an electron

Review: When atoms have the same number of protons (+) and electrons (-) they have no charge

Ex. Chlorine (Cl) has _____ protons and _____ electrons

Ex. Calcium (Ca) has _____ protons and _____ electrons

Ex. What happens is Cl gains one electron? Is it still neutral or does it have a charge?

Ex. What happens if Ca loses two electrons?

3.2 Ionic Compounds

(+) and (-) signs are placed in the upper right hand corner of the element symbol to indicate it's charge.

Here are some common ions. Fill in the table indicating whether they have gained or lost electrons or by writing the symbol:

Symbol Gained / Lost Electrons

H+

O2-

Na+

Copper loses 2 electrons

Sulfur gains 2 electrons

November 30, 2011

3.2 Ionic Compounds

Common ion charges are shown in the periodic table in the upper right corner of each element. Can you see any patterns?

Individual atoms can be ionic or groups of atoms can form ions. Ions with more than one element are called polyatomic.

Here are some common polyatomic ions:

CO32- = Carbonate

SO42- = Sulfate

Some elements can also form different ions depending on the number of electrons they lose or gain.

For example, Copper can lose either one or two electrons and become either

Cu+ or Cu2+

3.2 Ionic Compounds

Ionic compounds are made by combining a metal ion (with a positive charge) and a non-metal ion (with a negative charge)

Examples:

Na+ + Cl - NaCl (Sodium Chloride)

Li+ + Cl - LiCl (Lithium Chloride)

Ca2+ + Cl - CaCl2 (Calcium Chloride)

Ca2+ + CO 32- CaCO3 (Calcium Carbonate)

November 30, 2011

3.2 Ionic Compounds

Ionic compounds are neutral and thus the charges need to be balanced (equal zero)

Examples:

Barium + Chlorine =

Magnesium + Iodine =

Copper (II) + Chlorine =

Potassium + Carbonate =

3.2 Ionic Compounds

Lab: Properties of Ionic Compounds

ObservationsTest #1Distilled Water

Test #2Glucose Solution

Test #3Sodium SulfateSolution

Conclusions: Ionic compounds conduct electricity

November 30, 2011

3.2 Ionic Compounds

Lab: Properties of Ionic CompoundsUse the Setup described on page 145 of the textbook.

Changes to the lab:

You will be observing the reactions that occur in the petri dish with three different solutions:

1. distilled water2. sugar solution (non-ionic compound) - mix in 1 sm. teaspoon3. sodium sulfate solution (ionic compound) - mix in 1 sm. teaspoon

*Rinse out petri dish in between each test*Use approx. 4-6 drops of bromothymol blue (universal indicator) for each test

Conclusion: Which compounds are good electrical conductors? What happens when an electrical current is allowed to travel through water?

3.2 Ionic Compounds

Naming Ionic Compounds:

When naming ionic compounds, the name of the metal (first element) remains the same and the name of the non-metal ends with '...ide'

Also, when there is more than one ion charge possible (copper, iron etc), we use roman numerals to indicate which charge:

Ex. BaI2

Sc2S3

Ex. FeCl3

FeCl2

November 30, 2011

3.2 Ionic Compounds

Homework:

p.149 #1-5, 7-9

3.3 Molecular Compounds

Molecular compounds are different from ionic compounds in that they:

- are made when non-metals combine (as opposed to ionic compounds which are a metal and a non-metal)- can be solid, liquid, or gas at room temperature- are insulators (poor conductors)- low melting and boiling points

Molecular compounds don't have have ion charges so they are not as easy to predict as ionic compounds.

Subscript numbers are still used to indicate the number of atoms:

Ex. NH3, C6H12O6, H2O, H20, H2

November 30, 2011


Naming Molecular Compounds:1. The first element uses the element's name2. The second element has the suffix '-ide'3. We use a prefix when there is more than one atom:

mono = 1di = 2tri = 3tetra = 4penta = 5

4. The exception to rule #3 is that when there is only one of the first atom, we don't use 'mono'

Ex. H2OH2O2

CCl4PF5


Homework: p.153 # 1-7p.154 # 2-14

November 30, 2011

4.1 Chemical Reactions

Reactants: materials at the start of a chemical reaction

Products: new materials produced by the reaction

Endothermic: a chemical reaction that absorbs heat energy (gets colder)

Exothermic: a chemical reaction that releases heat energy (gets warmer)

Let's start with the boring stuff: definitions...


C6H8O7(aq) + 3NaHCO3(aq) --> 3H2O(l) + 3CO2(g) + Na3C6H5O7(aq)

Citric Acid Sodium Bicarbonate Water Carbon Dioxide Sodium Citrate

What are the reactants?

What are the products?

Is it endo or exothermic?

November 30, 2011


FeCl3(aq) + NaOH(aq) --> Fe(OH)3(s) + NaCl(aq)Iron (III) Chloride Sodium Hydroxide Iron (III) Hydroxide Sodium Chloride





Mg(s) + H2SO4(aq) --> MgSO4(aq) + H2(g)Magnesium and Sulfuric Acid produce Magnesium sulfate and Hydrogen gas




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CH3COOH(aq) + NaHCO3(s) --> CH3COONa(aq) + H2CO3(s)

H2CO3(aq) --> H2O(l) + CO2(g)

Acetic Acid (Vinegar) Sodium Carbonate Sodium Acetate Carbonic Acid (Baking Soda)




Carbonic Acid Water Carbon Dioxide


Chemical Changes involving oxygen:

Combustion: and exothermic reaction of oxygen with some fuel to produce carbon dioxide and water vapour

Corrosion: a slow chemical change that occurs when oxygen reacts with metal (ex. rust)

Cellular respiration: oxygen is used to help convert some food (glucose) into carbon dioxide, water, and energy that our bodies can use

And now for more boring stuff...

November 30, 2011



4.2 Conservation of mass in Chemical Reactions

200g

100g5g

What will the total mass be after the vinegar and baking soda are mixed together?

305g?

More? Less?

What if we cover the beaker?

CH3COOH(aq) + NaHCO3(s) --> CH3COONa(aq) + H2O(l) + CO2(g)

November 30, 2011


Read the lab on page 164

Lab Skills- Using a scale- Careful not to cross contaminate- Using a graduated cylinder

Precautions- bromothymol blue will stain your clothes (and everything else)- Don't let pressure build up in bag

In groups, conduct the lab according to the procedure. Try it again, this time leaving the bag open during the reaction. As a group, answer the analysis questions and form a conclusion.


Law of Conservation of Mass: matter is not created or destroyed in a chemical reaction.

The mass of the reactants always equals the mass of the products.

Open System: products are allowed to escape

Closed System: products are trapped / retained

Homework: #4-7, 9, 10

November 30, 2011

4.3 Factors Affecting the Rate of Chemical Reations

Who can make the juice the fastest?


There are 4 factors that affect how quickly a reaction occurs:

1. Concentration of the reactants

2. Temperature of the reactants

3. Surface area of the reactants

4. Presence of a CatalystA catalyst is a substance that helps a reaction

go faster. In a biology context, these are calledenzymes.

Which makes the reaction go faster? (Circle one)

High Concentration / Low Concentration

Cold Reactants / Warm Reactants

High Surface Area / Low Surface Area

Catalyst Present / Catalyst Absent

90% HCl 10% HCl

5oC 30oC

Asprin in Tablet Form

Asprin in Powder Form

Intestine produces lactase

Intestine does notproduce lactase

November 30, 2011


Hydrogen Peroxide catalyst demo

H2O2 --> H20 + O2(g)

This happens very very slowly unless a catalyst is added:

- Sunlight can be a catalyst

- Manganese (IV) Oxide MnO2(s)- Liver Enzymes

Scientific MethodMorgan enjoyed making film canister rockets so much in Mr. Korotash's Science class that he took it up as a hobby. He spends a Saturday afternoon trying to perfect the technique so that the film canister goes as high as it possibly can.

What are some different techniques Morgan can try? What can he change about his setup to try and maximize the height?

All good scientific experiments have clear manipulated and responding variables. The researcher must also control other factors to make sure they don't influence the results.

Manipulated Variable: what is being changed about the experiment

Responding Variable: what is being measured, observed, recorded (results)

Controls: Aspects of the experiment that are purposely kept constant so as not to affect the results.

November 30, 2011

Scientific MethodMorgan decides to see what the optimal amount of water is to make the film canister go the highest. He decides to try it with 5 mL, 7.5 mL, 10 mL, 12.5 mL, 15 mL, 17.5 mL, and 20 mL.

For each test he uses the same film canister and only uses one alka-seltzer tablet. Also the temperature of the water is the same. He does not shake any of the canisters.

Morgan places a measuring tape on the wall and visual estimates the height that the canister flies.

What is the manipulated variable?

What is the responding variable?

List as many controls as you can.

If Morgan graphed his results, what kind of graph should he use? Which axes do the variables go on?

unit b: matter and chemical change

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