Post on 17-Jul-2020
transcript
Unit 1 - Chemical ProcessesChapter 1 - Chemical Nomenclature
Watch: “An Introduction to Chemistry”
Unit 1 - Chemical Processes 1 / 57
Part I - Chemicals in Action
This section will explore ionic and molecular chemical compounds. Wewill:
recognize the relationships among chemical formulas, composition,and names;
write the chemical formulas for ionic and molecular compounds, andname these compounds.
Unit 1 - Chemical Processes 2 / 57
Part II - Understanding Chemical Reactions
Chemical reactions can be classified according to the types of reactantsinvolved. We will:
balance chemical equations;
recognize the types of chemical equations.
Unit 1 - Chemical Processes 3 / 57
Part III - Controlling Chemical Reactions
This section will discuss the rates of chemical reactions. We will:
explain which factors affect rates of chemical reactions and why;
identify everyday examples of ways in which rates of reactions arecontrolled.
Unit 1 - Chemical Processes 4 / 57
Section 1.1 - Introduction to Chemistry
What is Chemistry?
Chemistry is the study of the properties of materials and the changes thatmaterials undergo.
Unit 1 - Chemical Processes 5 / 57
Why study Chemistry?
It is the central science, leading to a fundamental understanding of othersciences and technologies.
It is an extremely practical science that greatly impacts our daily living:
improvement to health care
conservation of natural resources
protection of the environment
provision of our everyday needs for food, clothing, and shelter
Using chemistry, we have discovefirebrick helpful pharmaceuticalchemicals, increased food production, and developed plastics.
Unit 1 - Chemical Processes 6 / 57
Classifications of Matter
Matter is the physical material of the universe. The tremendous variety ofmatter in our world is due to the combinations of only about 100 verybasic substances called elements.
How can we classify matter?
Unit 1 - Chemical Processes 7 / 57
Unit 1 - Chemical Processes 8 / 57
Pure Substances
A pure substance is matter that has distinct properties and acomposition that doesn’t vary from sample to sample.
Examples:
Water
Oxygen
Table salt
All substances are either elements or compounds.
Elements are composed of only one kind of atom (ex: O, H, Fe).
Compounds are substances composed of two or more elements(water, table salt).
Unit 1 - Chemical Processes 9 / 57
Properties of Matter
Physical property - is a characteristic of a substance.
Example: Baking soda is a pure substance that is white, solid at roomtemperature, and dissolves readily in water (ex. changes of state).
Physical Change - a change in the size or form a substance which doesnot change the chemical properties.
Freezing - liquid to solid
Melting - solid to liquid
Boiling - liquid to gas
Condensation - gas to liquid
Sublimation - solid to gas
Unit 1 - Chemical Processes 10 / 57
Chemical property - a characteristic behaviour that occurs when asubstance changes to a new substance.
New substance is formed
Gas is produced
Colour change
Difficult to reverse
Heat or light is given off
Solid is formed
Unit 1 - Chemical Processes 11 / 57
Section 1.2 - Chemical Safety Symbols
Hazardous Household Product Symbols (HHPS)
Toxic - substances that even insmall quantities may poison,cause injury or death whenswallowed, absorbed through theskin, or inhaled into the lungs.
Flammable - substances, usuallyliquids, that can readily ignite(burn in air) in a wide range oftemperature conditions.
Unit 1 - Chemical Processes 12 / 57
Corrosive - substances orvapours that can deteriorate oreat away the surface of anothermaterial.
Reactive/Explosive -substances that can react withair, water, or another substanceto produce toxic vapours orexplode.
Watch: “Sodium in Water”
Unit 1 - Chemical Processes 13 / 57
Degree of Danger - combinedwith these three symbols, theprevious classification imagesshow the type and extent towhich a substance can beharmful.
Unit 1 - Chemical Processes 14 / 57
Workplace Hazardous Materials Information System (WHMIS)
Class A: Compressed gas
Class B: Flammable andcombustible material
Class C: Oxidizing Materials
Unit 1 - Chemical Processes 15 / 57
Class D: Poisonous and infectious materials
Division 1: Materials Causingimmediate and Serious ToxicEffects
Division 2: Materials CausingOther Toxic Effects
Division 3: BiohazardousInfectious Material
Unit 1 - Chemical Processes 16 / 57
Class E: Corrosive material
Class F: Dangerously reactive material
NFPA - National Fire ProtectionAgency
Unit 1 - Chemical Processes 17 / 57
Exit Slip
URL: http://goo.gl/LTRNYX
Recall:
Matter is the physical material of the universe.
All matter is composed of elements.
All elements are composed of very small particles called atoms.
What are atoms made up of?
Unit 1 - Chemical Processes 18 / 57
Atomic structure:
Atoms contain two main regions called the nucleus and the electroncloud.
The nucleus is composed of two subatomic particles called protonsand neutrons.
The electron cloud is composed of one subatomic particle called theelectron.
(a) The Bohr Model (b) The Electron Cloud Model
Unit 1 - Chemical Processes 19 / 57
The charges of the three key subatomic particles:
Protons - Positively charged. Denoted: p+
Neutrons - Neutrally charged. Denoted: n0
Electrons - Negatively charged. Denoted: e–
Elements on the Periodic Table are in electronically neutral form; i.e.they carry no charge. To be electronically neutral, an atom must have anequal number of protons and electrons.
Example: Which atom below is electronically neutral?
Unit 1 - Chemical Processes 20 / 57
Question:
Label the following diagram:
Unit 1 - Chemical Processes 21 / 57
Section 1.3 - The Periodic Table
Periodic Table - A structured arrangement of elements that allows us toexplain and predict physical and chemical properties.
Unit 1 - Chemical Processes 22 / 57
Chemical Families or Groups - Elements in the same vertical column ofthe periodic table. They tend to have similar physical and chemicalproperties.
Unit 1 - Chemical Processes 23 / 57
Symbols on the Periodic Table
Unit 1 - Chemical Processes 24 / 57
Determining the number of protons, neutrons, and electronsin an atom:
For any element:
Number of protons = Atomic Number
Number of electrons = Number of Protons = Atomic Number
Number of Neutrons = Mass Number - Atomic Number
Examples - Calculate the number of protons, neutrons, and electrons inthe following atoms:
1 Lithium
2 Krypton
3 Sodium
4 Potassium
Unit 1 - Chemical Processes 25 / 57
Section 1.4 - Bohr Diagrams: A Model for an Atom
Each shell or orbit can hold only a certain number of electrons.1 First orbit - 2 electrons2 Second orbit - 8 electrons3 Third orbit - 8 electrons4 Fourth orbit - 2 electrons
The valence shell of an atom is the outermost orbit. The electrons in thisorbit are called valence electrons.
Unit 1 - Chemical Processes 26 / 57
Examples:
Draw Bohr diagrams for the following:
1 a helium atom
2 a carbon atom
Identify how many valence electrons are present in each. Include thenumber of protons and neutrons in the nucleus.
Unit 1 - Chemical Processes 27 / 57
Practice:
Draw Bohr diagrams for the following:
1 a potassium atom
2 a nitrogen atom
Identify how many valence electrons are present in each. Include thenumber of protons and neutrons in the nucleus.
Unit 1 - Chemical Processes 28 / 57
The Nobel Gases
The nobel gases behave differently than other elements on the periodictable. Draw Bohr diagrams for the following:
1 Helium
2 Neon
3 Argon
What do you notice about the number of electrons in each orbit?
The nobel gases do not easily form compounds because their arrangementsof electrons are very stable. Their orbits are full.
Unit 1 - Chemical Processes 29 / 57
When elements have the opportunity, they will give, receive, or shareelectrons so that their electron arrangements match the most stableelectron arrangement of the closest nobel gas.
Example: How could lithium obtain an electron arrangement of itsclosest noble gas?
Unit 1 - Chemical Processes 30 / 57
Ions
Consider lithium (3 electrons). If lithium loses the electron in its outerorbit, than it’s left with 2 electrons - the same stable electron arrangementas helium. However, it still has 3 protons.
=⇒ It has formed an ion. When atoms gain or lose electrons theybecome ions.
Its ionic charge is now 3 + (−2) = 1. This is written as Li1+ or Li+.
Unit 1 - Chemical Processes 31 / 57
If an element loses electrons it becomes positively charged and is called acation.
Example: Li+
If an element gains electrons it becomes negatively charged and is calledan anion.
Example: F−
Unit 1 - Chemical Processes 32 / 57
Examples:
1 How many electrons does Na+ have? What type of ion is Na+?
2 How many electrons does Cl– have? What type of ion is Cl– ?
Unit 1 - Chemical Processes 33 / 57
Practice: What ionic charge would the following elements have to beclosest to a noble gas. How many elements would these ions have? Whattype of ions would they be?
1 Li, Na
2 Be, Mg
3 B, Al
4 C, Si
5 N, P
6 O, S
7 F, Cl
Unit 1 - Chemical Processes 34 / 57
How Elements Form Compounds
Much of chemical activity involves the transfer of electrons from onesubstance to another.
Ionic compounds are generally combinations of metals and nonmetals(cations and anions). These compounds are held together by attractionsbetween opposite charged ions (like a magnetic attraction). This is calledan ionic bond.
Molecular compounds are generally composed of nonmetals only.Electrons are shared between atoms. This is called a covalent bond.
Examples:1 MgCl2 (magnesium chloride)
2 H2O (water)
Unit 1 - Chemical Processes 35 / 57
Unit 1 - Chemical Processes 36 / 57
Examples: Using Bohr diagrams, show the complete electron transferthat results in the formation of the following ionic compounds.
1 NaCl
2 LiF
3 CaF2
Practice:
1 KCl
2 MgCl2
3 BeO
Unit 1 - Chemical Processes 37 / 57
Section 1.5 - Naming Ionic Compounds
Steps for naming binary ionic compounds:
1 Name the metal (cation) first.
2 Name the nonmetal (anion) second. For the nonmetal, drop theending and add “ide”.
3 Use Roman Numerals in parentheses to indicate which charge of themetal is used. This is only used for metals that make more than onecharge.
Unit 1 - Chemical Processes 38 / 57
Examples:
1 Ca3N2
2 Mg3P2
3 Al2O3
4 CuCl2
5 FeBr3
6 CoN
Unit 1 - Chemical Processes 39 / 57
Practice: Name the following compounds.
1 CaCl2
2 MgBr2
3 FeI3
4 CuCl2
5 Cr3N2
6 BeO
Unit 1 - Chemical Processes 40 / 57
Polyatomic Ions
Polyatomic ions - groups of atoms that tend to stay together and carryan overall ionic charge.
Examples:
nitrate - NO –3
hydroxide - OH–
bicarbonate - HCO –3
chlorate - ClO –3
sulfate - SO 2–4
phosphate - PO 3–4
Note: They are all anions!
Unit 1 - Chemical Processes 41 / 57
Steps for naming ionic compounds with polyatomic ions:
1 For polyatomic compounds, name the metal first followed by thename of the polyatomic ion. The endings do not change.
Examples:
1 Al(OH)3
2 NaHCO3
3 Sn(NO3)4
Unit 1 - Chemical Processes 42 / 57
Practice: Name the following compounds.
1 KNO3
2 Mg3(PO4)2
3 NaOH
4 Pb(NO2)4
Unit 1 - Chemical Processes 43 / 57
Section 1.6 - Writing Formulas for Ionic Compounds
Steps:1 Write the ionic charges above the symbols.2 Determine the lowest number of each element that would make the
entire compound electronically neutral.i.e. “Crisscross” the numbers, using them as subscripts. Remember
to reduce when appropriate.
Key fact: The sum of the charges on the positive ions equals the sum ofthe charges on the negative ions.
Examples:1 calcium iodide
2 sodium phosphide
3 calcium chloride
Unit 1 - Chemical Processes 44 / 57
Practice: Write the formulas for the following compounds.
1 sodium bromide
2 strontium nitride
3 potassium phosphide
4 magnesium nitride
5 zinc iodide
Unit 1 - Chemical Processes 45 / 57
Note: Some metals can make more than one kind of ion. Romannumerals in brackets indicate the charge of the ion (not how many are inthe formula).
Examples:
1 iron (III) oxide
2 iron (II) oxide
Unit 1 - Chemical Processes 46 / 57
Practice: Write the formulas for the following compounds.
1 cobalt (II) chloride
2 nickel (III) oxide
3 lead (IV) selenide
4 tin (II) nitride
5 iron (III) phosphide
Unit 1 - Chemical Processes 47 / 57
Note: Ionic compounds may include polyatomic ions. Reference the “Listof Polyatomic Ions” to determine the charges of the polyatomic ions.
Remember to put the entire polyatomic ion in brackets if you need morethan one!
Examples:
1 sodium carbonite
2 aluminum sulfate
Unit 1 - Chemical Processes 48 / 57
Practice: Write the formulas for the following compounds.
1 sodium chlorate
2 magnesium phosphate
3 silver nitrate
4 barium sulfite
5 iron (II) nitrite
Unit 1 - Chemical Processes 49 / 57
Section 1.7 - Molecular Compounds
Molecular compound - formed when nonmetals (anions) share electronswith other nonmetals (anions).
Covalent bond - a shared pair of electrons held between two nonmetalatoms that holds the atoms together.
Unit 1 - Chemical Processes 50 / 57
Examples: Using Bohr diagrams, show the complete electron sharing thatoccurs in the following molecular compounds.
1 H2
2 Cl2
3 H2O
Unit 1 - Chemical Processes 51 / 57
Practice: Using Bohr diagrams, show the complete electron sharing thatoccurs in the following molecular compounds.
1 F2
2 HF
3 CH4
Unit 1 - Chemical Processes 52 / 57
Diatomic Molecules
These are molecules composed of two of only one type of element.
The most common are:
H2 O2 F2 Br2 I2 N2 Cl2
Acronym: HOFBrINCl
Why would these atoms bond with themselves to form covalentbonds?
Unit 1 - Chemical Processes 53 / 57
Writing Formulas for Molecular Compounds
Steps:
1 Write the symbols of each nonmetal.
2 Write the appropriate subscripts for each nonmetal that correspondsto the prefixes used.
Note: The prefix “mono” is never used on the first nonmetal.
mono di tri tetra penta hexa hepta octa nona deca
1 2 3 4 5 6 7 8 9 10
Unit 1 - Chemical Processes 54 / 57
Examples: Write the formulas for the following molecular compounds.
1 carbon dioxide
2 dinitrogen trioxide
3 carbon tetrafluoride
Practice: Write the formulas for the following molecular compounds.
1 dihydrogen monoxide
2 diboron trioxide
3 phosphorus trihydride
Unit 1 - Chemical Processes 55 / 57
Writing Names for Molecular Compounds
Steps:
1 Write the name of the first nonmental and then the second.
2 Place the appropriate prefixes in front of each of the names. Theprefixes correspond to the subscripts of each element.
3 Drop the ending of the last element named and add -ide.
Note: Sometimes prefixes are shortened when the ending vowel of theprefix “conflicts” with a starting vowel in the compound. This makes thename easier to pronounce.
Unit 1 - Chemical Processes 56 / 57
Examples: Name the following molecular compounds.
1 CS2
2 N2O4
3 P4S10
Practice: Name the following molecular compounds.
1 CO
2 CF4
3 C2H6
Unit 1 - Chemical Processes 57 / 57