Science 10 Chemistry is the study of matter, its properties and its changes of transformations

Classifying Matter

MATTER Are the particles identical?

Y PURE SUBSTANCES Y N Are the atoms Identical?

N ELEMENTS COMPOUNDS SOLUTIONS MIXTURES COLLOIDS Tyndall Effect?

MECHANICAL MIXTURES

Properties of matter

Characteristics of Matter Physical

No New Substance Created

Chemical

New substance(s) created

Qualitative

(ie: methane is a Clear gas)

Quantitative

(ie: 10 L methane weighs 18.5 g

Qualitative

(ie: Colour change, Precipitate…)

Quantitative

(ie 2g H 2 O Makes 1 g H 2 + 1 g O 2

Using Chemical Properties

Tests for gases

O CO

2

CO

2

H

2 2

Property Observation Explain

Oxidizing agent Non-flammable Reacts with limewater Combustible / explosive if under pressure Reignites a smoldering splint Puts out a flaming splint O 2 rich environment allows faster burning CO 2 O 2 displaces the that is allowing the flame Turns cloudy in limewater Rapidly ignites when flame approaches the tube Forms an insoluble, white precipitate H 2 mixes and reacts with the O 2 that is in the tube

HHPS - WHMIS

The WHMIS and HHPS safety labeling systems are based on the chemical and physical properties of all substances deemed hazardous at home (HHPS) and in the workplace (WHMIS).

Elements and the Periodic Table

The structure of the periodic table is designed to help us explain and predict the physical and chemical properties, and atomic structure of each of the elements.

Periods : (rows) # of shells Families (columns): Similar Properties Same ionic charge Down and Left on table

More reactive

metals up and right on the table

More reactive

Predicting The Reactivity Of Elements (based on valance and # of shells) non-metals

Atomic Modeling

The

Bohr-Rutherford

models shows negatively charged electrons in orbits around a nucleus of positive protons and negative neutrons.

24 – atomic Mass (P + N) Mg 12 – atomic number (P = E) 12 P + 2 e 8 e- 2 e 12 N o 12 - N

Lewis Dot Diagrams

show the symbol surrounded by the electrons (represented by dots) in its valance shell oxygen with its 6 valance electrons the molecular compound ethane

Elements into Compounds

Atoms seek to become stable (full octet) by losing or gaining electron in their outer shell (valance shell). Sometimes they stabilize by forming ions, others they seek out others to share electrons and stabilize together.

Ionic Compounds

When a metals combine with non-metals they form an

ionic bond

between them. These compounds are soluble in water since the charged ions can disassociated.

Ie Na + Cl  Na + Cl -

Molecular Compounds

When non-metals combine they do not form ions. Instead electrons are shared, creating

covalent bonds

between them. These form molecules that do not disassociate and will only be soluble if polar Ie: 2 H + O  H 2 O 

Nomenclature - Ionic Compounds

Ionic compounds form between a positive metallic ions and negative non metallic ions, but the completed ionic compound is neutral. So…

The total charges on each side of the molecule must be equal.

ie: using lewis dot diagrams for calcium and iodine

Name of formula (non-metal – “ide”) So… Calcium Iodide

. .

.

Ca +

:

I

:

. .

.

:

I

. .

:

 [Ca] +2

. . . .

+ [

:

I

:

] [

:

I

:

. . . .

] -

Chemical formula



CaI 2

Here two iodine atoms are necessary to accept the two electrons offered by calcium. In accepting the electrons each iodine becomes negatively charged and the calcium becomes a +2 ion upon losing its two electrons…

Both sides of the formula have a total of 2 opposite charges



neutral

Nomenclature: More Than One Charge

Some elements, like copper (Cu + , Cu +2 ) and lead (Pb +2 , Pb +4 ), form more than one kind of ion. Use

UPC or Stock

systems when naming ions of metals that have more than one ionic charge. Compound formed between Fe +3 and O +2

Name

:

Iron (III) Oxide (or Ferric oxide) Formula:

So…

Fe +3 + O +2  2 Fe +3 + 3 O +2

Fe

2

O

3 Sometimes the Compound

FeO

is formed... What would it be called?

Since the oxygen ion has a charge of -2, the iron ion must have a charge of +2 to fulfill this 1:1 ratio.

So… Iron (II) Oxide (

or

Ferrous Oxide

)

Polyatomic Compounds

Polyatomic ions are groups of atoms that tend to stay together and carry overall ionic charge. Nitrate 

NO 3 -

looks like this: When naming compounds and writing formula the same basic premise that both sides of the formula must have equal/opposite total charges is in effect.

[

O O N O

]

-

Compound formed between Ammonium ion (

NH 4 +

) and Sulphate (

SO 4 -2

)

Name

: Ammonium Sulphate

Formula

: 2 (NH 4 + ) + SO 4 -2 

(NH

4

)

2

SO

4

Here two polyatomic ions of ammonium are necessary to neutralize the 2 negative charges provided by the sulphate polyatomic ion.

Nomenclature: Oxyacids

Oxyanion Formula NO 3 NO 2 SO 3 2 SO 4 2 PO 4 3 ClO 3 CO 3 2 Oxyanion Name nitrate nitrite sulfite sulfate phosphate chlorate carbonate Oxyacid Formula HNO 3 HNO 2 H 2 SO 3 H 2 SO 4 H 3 PO 4 HClO 3 H 2 CO 3 Oxyacid Name nitric acid nitrous acid sulfurous acid sulfuric acid phosphoric acid chloric acid carbonic acid

Remember:

H + , ite always one less “O” than ate but same charge, and ate:ic, and ite:ous.

Molecular Compounds

Diatomic elements (HOFBrINCl) 2 form between them are covalent. always form in pairs. The bonds that Other molecular compounds that form covalent bonds use the following prefixes for the anion: mono, di, tri, tetra, pent(a).

Molecular Compounds

: Hydrocarbons

Hydrocarbons are the simplest of the organic compounds. As the name suggests, hydrocarbons are made from hydrogen and carbon.

Alkanes

The alkanes are a family of hydrocarbons that share the same general formula. This is: CnH2n+2 Notice that double bonds can be formed with some of these

Synthetic Substances

Tiny molecules strung in long repeating chains form polymers. Why should you care? Well for one thing, your body is made of them. DNA, the genetic blueprint that defines people and other living things, is a polymer. So are the proteins and starches in the foods we eat, the wheels on our skateboards and in-line skates, and the tires on our bikes and cars. In fact, we’re surrounded by polymers every day, everywhere we go.

RNA formation polyethylene Glycogen – muscle sugar Copper-nanopolymers sandwich sticks like glue

Describing Chemical Reactions

The Law of Conservation of Mass states, in a chemical reaction, the total mass of the reactants is always equal to the mass of the products.

What goes into the reaction must come out (and vice versa)!

Ex: Water is broken down into hydrogen and oxygen when electrolyzed!

Word Equation Skeleton Equation

water

(l) 

oxygen

(g)

+ hydrogen

(g)

H

2

O



H

2

+ O

2

Balanced Equation

2(H = 2 O =1) 2(H = 2) 0 = 2 2 H

2

O



2 H

2

+ O

2

Types of Reactions - Combustion

A combustion reaction is a rapid chemical reaction of two or more substances (a fuel (e.g., wood, coal, oil, or natural gas) and an oxidizer) with a characteristic liberation of heat and light. (commonly called burning) Incomplete combustion,

when insufficient oxygen is available, can also cause the production of CO and C. Other impurities in the fuel can create by-products

Types of Reactions

A + B



AB Combination or synthesis

+ 

Decomposition AB



A + B

 +

Substitution or Single Replacement A + BC



B + AC

+  +

Metathesis or Double Displacement

+ 

AB + CD



AD + CB

+

Rates of reaction

Collision Theory – the rate of reaction is affected by the number of (effective) collisions of reactant molecules.

What affects the number of collisions?

Concentration Temperature Surface Area Catalyst (enzyme)

Acids

Acids are sour tasting, water-soluble substances. They are considered proton donors since the hydrogen ions that distinguishes them is displaced during the reaction.

Ions disassociated when dissolved in water HCl  H + + OH -

With metals, the H + is displaced to form H 2(g)

zinc + hydrochloric acid  hydrogen + Zinc chloride

With carbonates, water and carbon dioxide are formed.

Hydrochloric acid + calcium carbonate 

Common Acids

Acetic Citric acid Sulfuric acid Hydrochloric HC HC 6 H 7 O 7(aq) H 2 SO 4 HCl 2 H 3 0 2(aq) calcium chloride + water + carbon dioxide

Making acids

non-metal oxide + water  Acid

Bases

Bases are bitter-tasting, water-soluble substances that feel slippery to the touch. They are good conductors of electricity because they release OH , proton acceptors. Substances that are basic are described as alkaline. Common Bases Draino: drain cleaner (sodium hydroxide – NaOH) breaks down protein in hear Bleach: Sodium hypochlorite – NaClO Baking soda: Sodium bicarbonate – NaHCO 3

Making acids

Metal Oxide + Water  Base

The pH Scale

The pH scale represents how acidic or basic a solution is. The pH scale is a logarithmic scale. Which means that one unit on the scale represents a Tenfold effect on the concentration of the solution.

pH is defined as pH = -log 10 [H + ]

Therefore pH of 7 has 1.0 x 10 -7 pH of 1 has 1.0 x 10 -1 [H + ] or 1.0 x 10 -7 [OH ] [H + ] or 1.0 x 10 -13 ph of 9 has 1.0 x 10 -9 [H + ] or 1.0 x 10 -5 [OH [OH ] ]

Neutralization

Neutralization

: As you can see from the equations, acids solution and bases release OH . If we were to mix an acid together, the H + molecule H 2 ion would combine with the OH O, or plain water: ion release H and base to make the + into H + (

aq

) + OH (

aq

) H 2 O The neutralization reaction of an acid water and a salt , as shown below: with a base will always produce

Acid

HCl HBr + +

Base

NaOH KOH

Water

H 2 O H 2 O + +

Salt

NaCl KBr Common acid base reactions are: baking powder, plumbers use HCl, antacids, pool chemistry, hair products,