Science 1206Unit 3 – Chemical Reactions

Intro to Chemistry

Def’n: matter – anything that takes up space, which have both physical and chemical properties

Def’n: chemistry – the study of matter, its properties, and its changes or transformations

Q. How do we use chemistry in everyday life?

Laboratory Safety

Why is it important to have safety rules in a laboratory?

Textbook page 658 - 660

WHMIS

WHMIS is the Workplace Hazardous Materials Information System

It provides information about many hazardous materials used in the workplace

Employers are to ensure that their workers are trained in WHMIS if their workplace contains any hazardous materials

There are eight WHMIS symbols:

WHMIS

Class A: Compressed Gas

This class includes compressed gases, dissolved gases, and gases liquefied by compression or refrigeration.

WHMIS

Class B: Flammable and Combustible Material

This class includes solids, liquids, and gases capable of catching fire in the presence of a spark or open flame under normal working conditions.

WHMIS

Class C: Oxidizing Material

These materials increase the risk of fire if they come in contact with flammable or combustible materials.

WHMIS

CLASS D: POISONOUS AND INFECTIOUS MATERIALDivision 1: Materials Causing Immediate and Serious Toxic Effects

These materials can cause death or immediate injury when a person is exposed to small amounts. Examples: sodium cyanide, hydrogen sulphide

WHMIS

CLASS D: POISONOUS AND INFECTIOUS MATERIALDivision 2: Materials Causing Other Toxic EFFECTS

These materials can cause life-threatening and serious long-term health problems as well as less severe but immediate reactions in a person who is repeatedly exposed to small amounts.

WHMIS

CLASS D: POISONOUS AND INFECTIOUS MATERIALDivision 3: Biohazardous Infectious MATERIAL

These materials contain harmful micro-organisms that have been classified into Risk Groups 2, 3, and 4 as determined by the World Health Organization (WHO) or the Medical Research Council of Canada.

WHMIS

CLASS E: CORROSIVE MATERIAL

This class includes caustic and acid materials that can destroy the skin or eat through metals. Examples: sodium hydroxide, hydrochloric acid, nitric acid

WHMIS

CLASS F: DANGEROUSLY REACTIVE MATERIAL

These products may self-react dangerously (for example, they may explode) upon standing or when exposed to physical shock or to increased pressure or temperature, or they emit toxic gases when exposed to water.

MSDS

MSDS are the Materials Safety Data Sheets

They contain important information about an individual chemical

A sheet comes with a chemical when you order them

There are nine categories on a MSDS:

MSDS

Product Information: product identifier (name), manufacturer and suppliers names, addresses, and emergency phone numbers

Hazardous Ingredients Physical Data Fire or Explosion Hazard Data

MSDS

Reactivity Data: information on the chemical instability of a product and the substances it may react with

Toxicological Properties: health effects Preventive Measures First Aid Measures Preparation Information: who is

responsible for preparation and date of preparation of MSDS

MSDS

MSDS

Chemical Tests

Page 173 – 174; 290 There are several tests used to determine the

presence of certain chemicals:› For oxygen, we have the glowing stick test› For hydrogen, we have the lit splint test› For carbon dioxide, we have the lime water test› For water, we have the cobalt chloride paper test› For acids and bases, we have litmus paper.› For aqueous solutions of salt, we have the

conductivity test

Physical and Chemical Properties and Changes

Textbook page 173 Physical property – a characteristic of a

substance such colour, ability to conduct heat and/or electricity, lustre, smell, etc.

Chemical property – a characteristic behaviour that occurs when a substance changes to a new substance such as ability to burn, reactivity with water, pH, ability to rust, explosive, etc.

Physical and Chemical Properties and Changes

Physical change – a change in the appearance of a substance without changing the chemical make up of the substance such as a phase change, crumbling, dissolving, bending, etc.

Chemical change – a change in the chemical properties such as burning, rusting, reacting the chemical with another substance (e.g. vinegar in baking soda, etc.)

Physical and Chemical Properties and Changes

Generally speaking, physical changes are reversible (in theory) and chemical changes are not.

Worksheet Page 175 #4, 5

Formation of Ions

Recall that atoms are the basic building block of matter.› Each atom contains subatomic particles

(protons, neutrons, and electrons)› Protons are positively charged, neutrons

are neutral, and electrons are negatively charged.

› Protons and neutrons make up the middle, or nucleus, of an atom while the electrons fly around it in various energy levels

Formation of Ions

The outer most level is known as the valence electron level. It is in this level that electrons are either gained or lost.

Atoms want to have full electron levels in order to be stable.› Not the Noble gases have full valence

levels and, therefore, do not form ions.› In order to become stable atoms will lose

or gain electrons (whichever is least) to form simple ions (only one charged atom).

Formation of Ions

Formation of Ions

Metals (the left side of the periodic table) always lose electrons to obtain the nearest noble gas configuration.› These form cations› Since they lose electrons, these atoms now

have more protons than they do electrons and are, therefore, positively charged

› The group number (A’s) is the number of electrons which the atom will lose

Formation of Ions

Non-metals (right side of the periodic table) always gain electrons to obtain the nearest noble gas configuration.› These form anions› Since these gain electrons, these atoms

now have more electrons than protons and are, therefore, negatively charged

Worksheet #1

Bohr Diagrams

Recall from last year that you can draw the electron levels in a Bohr diagram.

There are two ways to do this, either with circles (messy) or with lines

The number of energy levels in a Bohr diagram is equal to the row number in which the element is found.

Bohr Diagrams

Ex. Draw a Bohr diagram for each of the following:

1. Magnesium2. Chlorine

Bohr Diagrams for Ions

When drawing a Bohr diagram for an ion, we need to think about how an atom becomes an ion (by losing or gaining electrons).› We need to show this on the digram.› Note that all the Bohr diagrams for metallic

ions will look like the diagram for the Nobel Gas that proceeds it, while the Bohr diagrams for non-metallic ions look like the diagrams for the Noble Gas which comes after it.

Bohr Diagrams for Ions

Ex. Draw a Bohr diagram for each ion.1. Aluminium ion2. Fluoride ion

*Bohr diagram worksheet

Formation of Molecular Compounds

Page 189; 201 - 202

Formation of Molecular Compounds

Binary Molecular Compounds Involve the sharing of electrons resulting in

covalent bonding Composed of two non-metals Exist as individual molecules May or may not be in lowest whole number

ratios

Formation of Molecular Compounds

Formation of Molecular Compounds

Covalent Bonding (Molecular Compounds) Sharing of electrons

› the two non-metals both want to gain electrons (to be like the noble gases), since both cannot gain electrons at the same time they share.

The unit formed by a covalent bond is called a molecule (it is neutral it has no charge)

Formation of Molecular Compounds

Mono-atomic elements› Mono means one so these are elements that exist on

their own in nature.› Namely the noble gases:

He – helium Ne – neon Ar – argon Kr – krypton Xe – xenon Rn – radon

No need to memorize these as they are listed in the periodic table

Formation of Molecular Compounds

Diatomic molecular compounds› These are non-metals that exist in nature as two atoms

joined together.› They are:

H2 – hydrogen

O2 – oxygen

N2 – nitrogen

Cl2 – chlorine

F2 – flourine

Br2 – bromine

I2 - iodine

Formation of Molecular Compounds

Polyatomic molecular elements› These are non-metals that exist in nature with many

atoms joined together› These are:

S8 – sulfur

O3 – ozone

P4 – phosphorus (red)

P10 - phosphorus (white)

Keywords

Molecule – a neutral particle that is made up of two or more atoms that are joined together by covalent bonds

Molecular formula – chemical formula which denotes the number and type of different atoms in a molecule

Empirical formula – the simplest chemical formula that can be written for a compound (smallest whole number ratio of atoms

Keywords

For example, water has the molecular formula H2O and the empirical formula H2O since the atoms are already in the simplest form. Whereas hydrogen peroxide has the molecular formula H2O2 and the empirical formula HO.

Polyatomic ion – an ion that consists of two or more different non-metal atoms that are joined by covalent bonds

Keywords

Simple ion – an atom that carries an electrical charge; positively charged ions are called cations and negatively charges ions are called anions

Formula unit - the chemical formula with the least number of elements out of the set of empirical formulas having the same proportion of ions as elements. Ex. NaCl is the formula unit for the ionic compound sodium chloride.

Keywords

Aqueous solution – a solution in which water is the solvent

Electrolyte – a substance that dissolves in water, producing a solution that is able to conduct electricity

Nonelectrolyte – a substance that dissolves in water and does not produce a solution that conducts electricity

Naming Molecular Compounds

Page 203 - 204 Trivial names

› These are names on compounds that do not follow the guidelines put out by IUPAC.

› These are: H2O – water

H2O2 – hydrogen peroxide

NH3 – ammonia

C12H22O11 – sucrose

Naming Molecular Compounds

For binary molecular compounds, we use prefixes to indicate the number of atoms that are present in the compound. These are:› Mono – one› Di – two› Tri – three› Tetra – four› Penta – five› Hexa – six› Hepta – seven› Octa – eight› Nona – nine› Deca - ten

Naming Molecular Compounds

When writing the name of a molecular compound start with the first element, not changing the name except for the prefix. Then write the name of the second element with the prefix and changing the ending of the name to –ide.

Note: the prefix mono on the first element only is optional.

Naming Molecular Compounds

For example, name the compound CCl4

The first element is carbon and there is only one of them.

The second element is chlorine and there are 4 of them. Therefore the name would be

monocarbon tetrachloride

or

carbon tetrachloride

Naming Molecular Compounds

Ex 2. Write the IUPAC name for P4F6.

Sol’n: The first element is phosphorus and there are four atoms.

The second element is flourine and there are six atoms. Therefore the name of this compound is:

tetraphosphorus hexafluoride

Naming Molecular Compounds

Your turn. Name each of the following.

1. P4F5

2. C2O4

3. NO3

4. Cl2O

5. N3Br2

6. O6I2

Writing Molecular Formulas

When writing molecular formulas you look up each element on the periodic table to determine the chemical symbol for the element. (Don’t forget that the ending on the second element has been changed to –ide)

Use the prefix on each element to determine the number of atoms present. Write this number to the right of the symbol and as a subscript.

Writing Molecular Formulas

Ex. Write the formula for diboron hexahydride.

The first element is boron which is B and di means 2.

The second element is hydride (or hydrogen) which is H and hexa means 6.

We have B2H6

Writing Molecular Formulas

Ex. Write the formula for nitrogen triiodide.

The first element is nitrogen which is N and since there is no prefix there is only one.

The second element is iodide (or iodine) and tri means 3.

We have N1I3 or NI3.

Writing Molecular Formulas

Your turn. Write the formulas for each of the following.

a. Carbon disulfide

b. Dinitrogen pentabromide

c. Silicon trifluoride

d. Hexaphosphorus pentachloride

Worksheet #2

Ions Forming Compounds

Ionic Compounds: Involve the transfer of electron(s), i.e. gaining and

losing electrons, resulting in ionic bonding Made up of two oppositely charged ions (metal and

non-metal, or combination involving a polyatomic ion)

Exist in the form of an ionic crystal lattice (not individual molecules)

Are always written as empirical formulas (lowest whole number ratio)

Ions Forming Compounds

Ions Forming Compounds

Ions Forming Compounds

Ions Forming Compounds

Naming Ionic Compounds

Page 192 - 194 There are three categories of ionic compounds

that we will deal with.

1. Binary ionica) Simple ions (only single charges)

b) Multivalent ions (more than one charge)

2. Polyatomic ions (complex ions)

3. Hydrates

Naming Ionic Compounds

Binary ionic compounds are composed of a metal ion (+) and non-metal ion (-).› Binary simply means that only 2 ions are involved.

Ex. NaCl – the combination of a sodium ion and a chloride ion.

Naming Ionic Compounds

Rules for naming simple binary ionic compounds (meaning a compound with only two elements:

1. Name the cation (+) by writing the full name of the metal.

2. Name the anion (-) by shortening the name of the atom and adding the –ide ending.

Naming Ionic Compounds

Ex. NaCl sodium chloride

CaF2 calcium fluoride

K2O potassium oxide

**Note: Do NOT use prefixes – they are for molecular compounds only (i.e. two non-metals)

Naming Ionic Compounds

Your turn. Name the following:

1. LiBr

2. AlCl3

3. Rb2S

4. Mg3P2

5. CaO

Writing Ionic Formulas

Rules for writing binary ionic formulas:

1. Write down the symbols of the ions involved.

2. Cross over the charges and write as subscripts.

3. Determine the lowest whole number ratio of ions that will give a net charge of zero.

4. You do not need to write 1’s.

Writing Ionic Formulas

Ex. 1) Write the chemical formula for potassium bromide.

2) Write the chemical formula for calcium oxide.

3) Write the chemical formula for magnesium iodide.

Writing Ionic Formulas

Your turn. Write the chemical formula for each compound:

1. Sodium sulfide2. Aluminum bromide3. Barium iodide4. Magnesium nitride5. Aluminum nitrideWorksheet #3

Naming Multivalent Ionic Compounds

Page 195 Ions of certain elements can have more than one

possible charge. Such elements are called multivalent species.

Ex. Copper is multivalent its ions can have either a 1+ or 2+ ion charge (Cu+ or Cu2+)- these charges are provided on the periodic table

These multivalent elements are all transition metals

Naming Multivalent Ionic Compounds

When we name these compounds we need to indicate which ion we are using and we do this by using Roman numerals to represent the ionic charge. (Do worry if you don’t know your Roman numerals as they are written on your periodic table of ions, but if you plan on doing Chemistry 2202/3202 you will need to know them)

Naming Multivalent Ionic Compounds

Roman numerals:› One – I› Two – II› Three – III› Four – IV› Five – V› Six – VI

Naming Multivalent Ionic Compounds

Rules for naming multivalent binary ionic compounds:

1. Determine if the metal has more than one possible charge (i.e. multivalent)

consult periodic table

2. “Uncross” the subscripts and write them as ionic charges. I.e. work backwards.

Naming Multivalent Ionic Compounds

3. See if that charge is there on the periodic table for that element. If not then you will have to look up the charge on the anion (i.e. the non metal) and see what scale factor to use.

4. Write the name of the compound. Be sure to indicate the identity of the metal ion with Roman numerals.

Naming Multivalent Ionic Compounds

Ex 1. Write the IUPAC name for SnCl4.

**See other board for solution.

Ex 2. Write the IUPAC name for CrBr3.

**See other board for solution.

Naming Multivalent Ionic Compounds

Your turn. Write the names for the following compounds:

1. TiO2

2. AuCl3

3. Fe2O3

4. AgI

Writing Multivalent Ionic Formulas

These are done in the same manner as binary ionic compounds.

Use the Roman numeral to determine the ionic charge on the cation (i.e. the positive ion)

Ex. Write the chemical formula for iron (II) chloride.

**See other board for solution.

Writing Multivalent Ionic Formulas

Your turn. Write chemical formula for the following compounds:

1. Titanium (III) fluoride

2. Titanium (IV) fluoride

3. Nickel (II) oxide

4. Lead (IV) sulfide

5. Vanadium (V) oxide

Worksheet #4

Naming Compounds with Polyatomic Ions

Page 196 - 198 A polyatomic ion is two or more atoms

covalently bonded together that carry an overall charge. Since they have a charge they can gain or lose electrons to form ionic compounds.

These ions are listed on your periodic table of ions but this list is not exhausted, i.e. There are more polyatomic ions than what’s listed.

Naming Compounds with Polyatomic Ions

To identify these compounds look at the elements involve. If you have more than two elements in the compound and the compound is not in your trivial names list than it contains a polyatomic ion.

You name these the same way you name ionic compounds: look up the element/polyatomic ion and write the names down not changing the second name to have the ending –ide.

Naming Compounds with Polyatomic Ions

Ex 1. (NH4)3PO4

**See other board for solution

Ex 2. Cr(NO3)3

**See other board for solution

Naming Compounds with Polyatomic Ions

Your turn. Write the name of the following compounds.

1) Zn(OH)2

2) Pb(NO3)2

3) Mg(CH3COO)2

4) Na3BO3

5) K2Cr2O7

Writing Compounds with Polyatomic Ions

When writing the formulas for compounds containing a polyatomic ion(s), you treat the ion as a single unit, not as individual elements.

If you need to write a subscript for a polyatomic ion, then you must enclose the ion in brackets.

Remember to use the charges on the polyatomic ions to determine how many you need to have a balanced compound, NOT the subscripts!!!

Writing Compounds with Polyatomic Ions

Ex 1. sodium chlorite

**See other board for solution

Ex 2. iron (III) sulfate

**See other board for solution

Ex 3. ammonium permanganate

**See other board for solution

Writing Compounds with Polyatomic Ions

Your turn. Write the formula for each of the following.

1. Sodium hydroxide

2. Potassium bicarbonate

3. Potassium carbonate

4. Magnesium hydroxide

5. Ammonium sulfate

Worksheet #5

Ionic Hydrates

Page 236

Def”n: ionic hydrates – a compound that has water associated with it. Water is part of its crystalline structure.

Ex. Bluestone (CuSO45H2O) contains five water molecules per copper (II) sulfate molecule in the crystal.

Def’n: anhydrous – without water.

Ex. Anhydrous bluestone is CuSO4

Writing Formulas for Ionic Hydrates

When writing formulas for ionic hydrates, you write the formula for the ionic compound as already learned and add on H2O.

Hydrates use the same prefixes as molecular compounds to indicate how many water molecules are associated with compound.

To tell whether or not you have a hydrate or not, you look for the word hydrate.

Writing Formulas for Ionic Hydrates

Ex. Write the chemical formula for each hydrate:

a) Sodium thiosulfate pentahydrate

**See other board for solution

b) Copper (II) sulfate pentahydrate**See other board for solution.

Writing Formulas for Ionic Compounds

Your turn. Write the formulas for each of the following.

1. Zinc sulfate heptahydrate

2. Potassium sulfate decahydrate

3. Cadmium nitrate tetrahydrate

Naming Ionic Hydrate Compounds

Name the ionic compound as already learned and add on hydrate with the appropriate prefix.

Ex. Write the name for:

1. Ni3(PO4)28H2O

**See other board for solution

2. Fe(OH)33H2O

**See other board for solution

Naming Ionic Hydrate Compounds

Your turn. Name the following compounds.

1. CuSO4∙5H2O

2. NiCl2∙6H2O

3. CoCl2∙5H2O

Worksheet #6

Core Lab #5: Properties of Ionic and Molecular Compounds

Complete the Pre-lab Activity Complete the lab activity and prepare a

lab report following the handout. Attach answers to questions to the

back of the report. Go back and complete the chart –

Properties of Ionic and Molecular Compounds p. 23

Acids and Bases

Page 288 – 290 Page 293 – 294 Page 295

Acids and Bases

Def’n: acids – molecules that ionize in water to produce hydrogen ions (H+)

The properties of acids include: Turn blue litmus paper red React with metals to produce hydrogen gas Neutralize bases Have low pH (<7) Taste sour

Acids and Bases

Def’n: base – ionic compounds that contain the hydroxide ion (OH¯)

The properties of bases include: Turn red litmus blue Neutralize acids High pH (>7) Form slippery solutions Bitter taste

Acids and Bases

Salts are formed as a result of the reaction between an acid and a base› Salts form electrolytic solutions when dissolved in

water

Acid + Base Salt + Water

Ex. HCl(aq) + NaOH(aq) H2O(aq) + NaCl(aq)

Note: There are more salts than just table salt (NaCl)

Naming Acids and Bases

To distinguish acids and bases from other types of compounds look for (aq) next to the chemical formula which means that the compound is dissolved in water which acids and bases need to be.

Name bases the same way you name any ionic compound.

Naming Acids and Bases

Naming acids depends on the anion (negative ion)› If the anion is an element or a polyatomic ion ending

with –ide then

1. Drop the –gen ending of hydrogen

2. Replace the –ide ending of the anion with –ic

3. Add the word acid

Ex. HCl(aq) hydrochloric acid

Naming Acids and Bases

› If the anion is polyatomic and ends with –ate

1. Drop the name hydrogen

2. Replace the –ate ending of the anion with –ic

3. Add the word acid

Ex. HClO3(aq) chloric acid

Naming Acids and Bases

› If the anion is polyatomic and ends with –ite

1. Drop the name hydrogen 2. Replace the –ite ending of the anion with –

ous 3. Add the word acid

Ex. HClO2(aq) chlorous acid

Naming Acids and Bases

Note: With sulfur leave the –ur, for example, H2SO3(aq) sulfurous acid.

With phosphorus leave the –or , for example, H3PO4(aq) phosphoric acid

Naming Acids and Bases

Your turn. Name the following acids:

1. HBr(aq)

2. HNO3(aq)

3. HNO2(aq)

4. HCN(aq)

5. H2CrO4(aq)

6. HClO(aq)

Writing Acids and Bases

To write bases, you do the same as with any ionic compound.

To write acids, first convert the acid name to the asscotiated ionic name

Hydro________ic acid hydrogen _______ide

________ic acid hydrogen _______ate

_________ous acid hydrogen _________ite Then write the formula as you learned previously.

Writing Acids and Bases

Ex 1. hydroiodic acid

Ex 2. boric acid

Ex 3. Nitrous acid

Writing Acids and BasesYour turn. Write the formula for each of the

following.

1. Hydrofluoric acid

2. Carbonic acid

3. Sulfurous acid

4. Hydrosulfuric acid

5. Perchloric acid

6. Silicic acid

Worksheet #7

When Acids and Bases are Mixed

Page 314 Page 317 – 319 Neutralizations reaction – mixing an

acid with a base (or vice versa) to temper (reduce) the effects of one or the other› Produces water and a salt

Salt – an ionic compound that will conduct electricity when dissolved in water (aqueous)

When Acids and Bases are Mixed

› Salts do NOT change the colour of litmus paper

Generalized neutralization reaction:Acid + Base → Water + Salt

For example, hydrochloric acid + sodium hydroxide → water + sodium chloride

When Acids and Bases are Mixed

Applications of neutralization reactions› Using lemon juice (acidic) to eliminate fish

odors (base)› Using TUMS (basic) for heartburn (acidic)› Baking with baking soda (basic) and an

acid (like lemon juice or buttermilk) to make your cakes rise

› Cleaning up acid spills in the lab with baking soda (base)

pH Scale Page 296 The pH scale is a measure of how acidic or basic

a solution is. It ranges from 0 – 14, with 7 being neutral, less

than 7 being acidic and greater than 7 being basic.

The further from 7 you get in either direction results in a stronger acid/base.

Indicators are used to test for pH.