snc2p getting started. science science is a way of gaining knowledge and understanding of our world....

SNC2P

Getting Started

Science

• Science is a way of gaining knowledge and understanding of our world.

• It is the desire to understand how and why things work.

• Science, in its purest form, is done out of simple curiosity.

• It is concerned with knowledge and ideas.

Technology

• Technology is applying knowledge to make products that will improve the quality of our lives.

• It answers human needs.

• Technology is concerned with the production of things.

Hazardous Household Waste

• Household hazardous waste (hhw) is any substance that may be harmful to you, animals, or the environment when not properly handled.

• Hhw can be in the form of solids, liquids, or gases.

• Misuse of hhw can lead to pollution of groundwater, lakes, rivers, and soil.

• An easy way to identify hhw is to look at the label and read disposal instructions.

Hazardous Household Product Symbols

• Containers labeled with this symbol are explosive. They may produce deadly fumes or vapors when exposed to air Keep away from heat.

• Any product with this symbol is flammable. Keep away from sources of spark or flame.

Hazardous Household Product Symbols

• Products with this symbol are poisonous or lethal if swallowed, inhaled, or absorbed

• A product with this symbol is corrosive and can cause burns to your skin and eyes and can eat away at other material.

Degree of Danger

• The degree of danger of hazardous household products is indicated by the shape outlining the symbol.

• Danger –

• Warning –

• Caution –

Workplace Hazardous Materials Information System

WHMIS

• Workplace Hazardous Materials Information System was implemented in 1988 as a national system to provide information on hazardous materials used in the workplace.

• The key elements of the system are the material safety data sheets (msds), the simple labeling system, and the workers education program.

•The WHMIS Board contains all the symbols with

explanations.

• There is also a binder with the data sheets for

each chemical in the facility.

• This is a container of toluene.

• You can see the WHMIS label clearly by the dashed border and the hazard symbols.

WHMIS Symbols

• Compressed Gas – materials that are normally gaseous and kept under pressure. These may explode if dropped or exposed to pressure or heat.

• Flammables and Combustibles – materials which ignite easily and will continue to burn after being exposed to flame or spark.

WHMIS Symbols Continued• Oxidizing Material – materials

which can cause other materials to burn. Will cause combustibles to react violently Can cause skin and eyes to burn.

• Toxic, immediate and severe effects – poisonous and potentially fatal materials that will cause severe harm if inhaled, ingested, or absorbed (even in small amounts).

WHMIS Symbols Continued• Toxic, long term effects –

materials which may have harmful effects after repeated exposure. May cause death or permanent injury, birth defects, sterility, cancer, or even allergies.

• Biohazardous infectious – Infectious agents or biological toxins causing serious disease or death. Includes viruses, yeasts, molds, bacteria, parasites.

WHMIS Symbols Continued• Corrosive Materials – materials that

react and cause skin irritation, severe burns and tissue damage, lung damage, eye irritation or blindness, as well as environmental damage from fumes.

• Dangerously reactive material – these have unexpected reactions. They may react with water. They may be unstable in air. They may explode if exposed to shock or heat. May release toxic fumes or burn unexpectedly.

Labware

Beaker

Beaker tongs

Evaporating dish

Watch Glass

Wash bottle

Test tube

Test tube clamps

Test tube rack

Graduated cylinder

Florence flask

Erlenmeyer flask

Stirring rod

Pipette

Funnel

Wire screen (gauze)

Ring clamp

Ring stand

Goggles

Crucible

Crucible tongs

Triple Beam Balance

Pestle

Mortar and pestle

Bunsen Burner 

Scupula and handle

 Clay triangle

Striker

Set up for heating

Thermometer

Lab Safety

Lab Safety

• Always be safety conscious. Move around the laboratory in a safe and slow manner.

• Never perform unauthorized experiments. Follow all instructions, verbal and written.

• Plan ahead. Become familiar with all the health and safety hazards of the equipment and chemicals to be used. If you are not comfortable, inform the teacher.

• Know the location of the safety equipment and fire exits. Use this equipment only in emergencies.

• Report all accidents – no accident is too small to report. Do not attempt to clean up a spill until checking with the teacher. Broken glassware must be dealt with immediately. Inform teacher of all broken glassware.

• Safety glasses must be worn while working with any chemical. It is recommended that you do not wear contact lenses during labs where chemicals will be used. If you get chemical in your eye, do not wait for the teacher, have a peer take you straight to the eyewash station and flush eyes for 5 minutes.

• If you get chemical splashed or spilled on your skin, flush it with water at one of the sinks around the room. If irritation or pain develops, see a physician.

• Wash hands thoroughly before leaving the laboratory.

• If you get chemicals on your clothes, wash the clothes, but not with good clothing. You should not wear loose clothing in the lab, nor should you wear good clothing.

• Handle all chemicals as if they were dangerous.

• Tie back long hair.

• Do not consume food or drink while in the lab. Never taste the chemicals.

• Keep workstations clear of all books, bags, and clothing. Workstations should have only the materials needed for the lab. Do not sit on the workstation counter

• Clean all equipment thoroughly and put it back where you found it.

• Follow all directions regarding the disposal of chemicals and solutions. Not everything goes down the sink. Do not put used chemicals or solutions back into the original container.

• Clean your lab station before leaving the classroom.

Science 10

Chemical Reactions

Classification of Matter

• Matter can be classified into two main categories, pure substances and mixtures

Pure Substances

• Pure substances are made up of only one component.

• A pure substance may be further classified as either an element or a compound.

An Element

• An element is a type of matter that is made up only of one type of atom.

• Some examples are gold, silver, lead, and mercury.

• Elements are given chemical symbols to represent them.

• The first letter (or only letter) is always capitalized.

• The second letter (if there is one) is always lower case.

H is Hydrogen

O is Oxygen

Be is Beryllium

Ni is Nickel

Compounds

• Compounds are materials that are made of two or more types of atoms joined chemically.

• Some examples are water (H2O), carbon dioxide (CO2) and sodium chloride (NaCl).

Mixtures

• In a mixture, different substances are brought together without creating a new substance. The pieces mix but do not join.

• In a mixture, each component retains its own identity, however, the ratio of the components that make up the mixture can change.

• A regular bag of M& M's Chocolate Candies contains 20% orange and 13% brown candies, with the remaining 67% being split (unevenly) between green, blue, red and yellow. When M & M's sell for Halloween, the ratios of the colors change such that only orange and brown M & M's appear in the bag. This ability to change ratios is a characteristic of a mixture.

Properties of Matter

• There are two characteristics or properties that help determine forms of matter – physical properties and chemical properties.

Physical Properties of Matter• Physical properties describe what the

material is like. These are visible features that can be observed or measured.– State – solid, liquid, gas, plasma– Colour– Density, viscosity– Hardness, brittleness– Taste, odour, texture, lustre, clarity– Melting and boiling points– Ductility (bendable) and malleability (able to be

hammered)

Chemical Properties of Matter

• Chemical properties explain how a material behaves and reacts in relation to other materials.– Types of bonds– Reactivity– Isotopes formed

Changes in Matter

• Chemists classify changes in matter into two categories, physical change and chemical change.

Physical change

• A physical change when there is no new product formed. The particles of the starting substance are not changed. A physical change can easily be reversed.

Chemical Change• In a chemical change, the substance

changes identity into something else.

Clues that a Chemical Change Took Place

A new colour appearedHeat or light was given offBubbles of gas were given offA precipitate formedThe change is difficult to reverse

The Atom

• The atom is the smallest particle of an element that retains all of the properties of that element.

• The atom has three subatomic particles: the proton, the electron, and the neutron.

Element Names

• All known elements have names. These names are from several sources.

• Some names have been around for many years. They have a Latin or Greek Origin.

• Chlorine comes from the word chloros which means yellow-green.

More on Element Names

• Some elements are named after important scientists.

• Einsteinium• Curium

• Some elements are named after places or planets.

• Uranium and Mercury• Californium

Even More on Element Names

• Some more recent elements have not been named yet.

• Elements 110 to 114

Element Symbols

• Element symbols can be an abbreviation of the element’s name.

• Carbon is C• Nitrogen is N• Calcium is Ca• Magnesium is Mg

More on Element Symbols

• Element symbols can also be an abbreviation of the ancient name.

• Copper is Cu• Tungsten is W

Subatomic Particles

• A proton is a positively charged particle found in the nucleus. It is partly responsible for the mass of an atom.

• A neutron is a particle with no charge found in the nucleus of an atom. It is partly responsible for the mass of an atom.

• An electron is a negatively charged particle found outside the nucleus. Electrons are very small and do not add much to the mass of an atom.

Atomic Information From The Periodic Table

Atomic Charge

• Atoms are neutral, which means that there is no overall charge.

• The number of protons is equal to the number of electrons.

Protons Minus Electrons Equals

Charge

The Periodic Table

The Periodic Table

• The Periodic Table is the central tool of the chemist, but it is used by scientists in all fields of study.

• It was developed by Russian Scientist, Dmitri Mendeleev, in the 1800s.

• The more modern version of the table is credited to Henry Mosely.

The Periodic Table

• The periodic table is essentially a list of known elements. It gives information about each element and for that reason it is a very valuable tool.

Arrangement of the Periodic Table

• The horizontal rows (periods) represent a series of elements with increasing weight and changing properties.

Arrangement of the Periodic Table

• The vertical columns represent a series of elements with similar chemical and physical properties.

• The column are called families and each family has a specific name.

Examples of Some Families on the Periodic Table

Metals and Nonmetals• Elements on the Periodic Table can be divided into

metals and nonmetals. Metals are found on the left side of the zigzag line. Nonmetals are found on the right side of the zigzag line.

Metalloids

• Elements that touch either side of the zigzag line have some metal properties and some nonmetal properties. These are called metalloids.

Steps for Drawing Atoms

1. Find the element on the periodic table. How many protons does it have?

2. Because atoms are neutral, the number of electrons will equal the number of protons

3. Write the number of protons in the center.

4. Colour in the electrons. Start with the two closest to the nucleus and work outwards.

Drawing Atoms

• The first ring around the nucleus can hold a maximum of 2 electrons.

• The second ring around the nucleus can hold a maximum of 8 electrons.

• The third ring can around the nucleus can hold a maximum of 8 electrons.

• The fourth ring around the nucleus can hold a maximum of 18 electrons.

Electron Shells for the First 20 Elements

Making Ions

• The goal of every element is to have a full outer shell.

• Electrons are gained or lost in order to attain a complete outer shell.

Making Negative Ions

• Chlorine has 17 electrons. Seven of those electrons are in the outer shell. In order for Chlorine to have a complete out shell it has to gain one electron or lose seven electrons. It will gain one electron.

Making Positive Ions

• Sodium has 11 electrons. One of those electrons is in the outer shell. In order for sodium to have a complete outer shell it would have to gain seven electrons or lose one electron. It loses one electron.

Valence Electron Trends• Elements in the Alkali Metal Family (H, Li, Na, K, Rb,

Cs, and Fr) tend to lose 1 electron.• Elements in the Alkaline Earth Metal Family (Be, Mg,

Ca, Sr, Ba, and Ra) tend to lose 2 electrons.• Elements in the Boron Family (B, Al, Ga, In, and Ti)

tend to lose 3 electrons.

Valence Electron Trends

• Elements in the Carbon Family (C, Si, Ge, Sn, Pb) can gain or lose 4 electrons.

• Elements in the Nitrogen Family (N, P, As, Sb, Bi) tend to gain 3 electrons.

• Elements in the Oxygen Family (O, S, Se, Te, Po) tend to gain 2 electrons.

• Elements in the Halogen Family (F, Cl, Br, I, At) tend to gain 1 electron.

• Elements in the Noble Gas Family (He, Ne, Ar, Kr, Xe, Rn) do not tend to gain or lose electrons as their outer shells are already complete.

How to Draw Electron Dot Diagrams

• Imagine a square around the element symbol.

• Determine the number of valence electrons. – Alkali Metals have 1– Alkaline Earth Metals

have 2– Boron Family has 3

– Carbon Family has 4– Nitrogen Family has

5– Oxygen Family has 6– Halogen Family has

7– Noble Gas Family

has 8

More on How to Draw Electron Dot Diagrams

• When filling the sides with electrons, each side gets one electron before any side gets two.

• Start at the top and work clockwise around the box.

• Once each side of the box has two electrons, the shell is full.

• Beryllium

Be• Boron

B• Silicon

Si• Nitrogen

N

Forming Ions

• In an atom the number of protons equals the number of electrons.

• If electrons are added to an atom, the atom now has more negatives than positives. It has a negative charge. This is an anion.

• If electrons are removed from an atom, the atom now has more positives than negatives. It has a positive charge. This is a cation.

Naming Ions

• To name a Cation (positively charged ion), write the element name followed by the word ion.

Mg2+is calledMagnesium

Ion

• To name an Anion (negatively charged ion), write the name of the element and change the ending to “ide”

S2-is calledSulfide

Writing Ionic Symbols From Names

• When given the name of an ion and the ending does not have “ide”, then you know this is a positive ion.

• Write the element’s symbol with a positive charge (recall the valence electron trends to know what the charge is).

The symbol for Potassium Ion is

K1+

• When given the name of an ion that ends in “ide”, you know it is a negative ion.

• Write the element’s symbol with a negative charge (recall the valence electron trend to know what the charge is).

The symbol forNitride is

N3-

Transition Metals

• The elements in columns 3 to 12 are called the Transition Metals.

• Transition Metals are always positive.• To know what the charge is you will

have to look at the Roman Numeral in the name.

Iron (III) means Fe3+

Nickel (II) means Ni2+

Traditional and Stock System Names of Transition Metals

• You will be given a table of traditional names for transition metals.

• Some examples of traditional names are Ferrous (Fe2+) and Ferric (Fe3+).

• The system we mostly use in this class is the Stock System.

• In the Stock System, Fe2+would be Iron (II) and Fe3+would be Iron (III).

Forming Ionic Compounds

• Substances that are composed of cations and anions are called ionic compounds (compounds made up of ions).

• When the ions combine the overall charge of the compound that is formed must be neutral.

K+ and Cl-

will combine to form

KCl

Forming Ionic Compound Examples

• Ca2+ and Cl1- will form

CaCl2

Because it will take two negative chlorines to balance one positive calcium.

• Na+ and S2- will form

Na2S

Because it will take two positive sodiums to balance one negative sulfur.

• Al3+ and P3- will form

AlP

Because it will take one positive aluminum to balance one negative phosphorus.

• Al3+and O2- will form

Al2O3

Because it will take two positive aluminums to balance three negative oxygens.

The Trick to Forming Ionic Compounds

Be2+ and P3-

Take the number part of the charge and put it on the bottom left hand side of the other ion.

Be 3 P 2

Polyatomic Ions

• Atoms can combine in groups to form ion complexes. These are called polyatomic ions.

• An example of a polyatomic ion is Phosphate (PO4)3-

• Other examples are Sulfite (SO3)2- and Ammonium (NH4)1+

• There is a table of common polyatomic ions that will be available for you to use.

Forming Compounds Using Polyatomic Ions

• The trick that was used to make binary ionic compounds (compounds made from 2 ions) can also be used to form polyatomic compounds.

Mg2+ and (PO4)3-

forms

Mg3 (PO4)2

Naming Ionic Compounds When Given The Formula

• Identify the ions in the compound

• Name the ions in the compound

• Change the ending on the second element to “ide”

Na2S

Sodium and Sulfur

Sodium Sulfide

Another Example of Naming Ionic Compounds When Given The

Formula• Identify the ions in

the compound• Name the ions in the

compound• Change the ending

on the second element to “ide”

KCl

Potassium and Chlorine

Potassium Chloride

Another Example of Naming Ionic Compounds When Given The

Formula• Identify the ions in

the compound• Name the ions in the

compound• Change the ending

on the second element to “ide”

CaBr2

Calcium and Bromine

Calcium Bromide

An Example of Naming a Polyatomic Compound

• Identify the ions in the compounds.

• Name the ions in the compound (use the polyatomic ion chart).

• Put the two names together

Li(NO2)

Lithium and Nitrite

Lithium Nitrite

An Example of Naming a Compound

That has a Transition Metal • Identify the ions in the

compounds.• Name the ions in the

compound (remember that transition metals have to have a roman numeral in their name).

• Put the two names together

Ag(Cr2O7)

Silver (II) and Dichromate

**Dichromate has a charge of –2 and it only take one silver to cancel that charge out, silver must be +2

Silver (II) Dichromate

Writing a Compound Formula When Given the Name

• Identify the ions in the formula

• Write down the symbols and determine the charge using the valence electron trends

• Put the two ions together (cation goes first)

• Sodium Nitrate

Made up of sodium ion and Nitrate ion

• Sodium ion is Na+

Nitrate ion is NO3-

• Na+ and NO3- form

NaNO3

Another Example of Forming a Compound from a Name

• Identify the ions in the formula

• Write down the symbols and determine the charge using the valence electron trends

• Put the two ions together (cation goes first)

Copper (II) Chloride

made up of Copper (II) and Chloride

Copper (II) is Cu2+

Chloride is Cl-

Cu2+ and Cl-1 form

CuCl2

Forming Covalent Compounds

• Atoms that share electrons rather than take or give them up are bonded covalently.

• Neither atom is strong enough to take the electrons from the other.

• Covalent bonds often happen between two negatively charged ions.

• Naming covalent molecules is different than naming ionic compounds.

• Prefixes are used to indicate how many of each atom are in the molecule.

Covalent Molecule Prefixes

• Mono = 1• Di = 2• Tri = 3• Tetra = 4• Penta = 5• Hexa = 6• Hepta = 7• Octa = 8

Covalent Molecule Examples

• An example of a covalent molecule is P2O5

This would be called Diphosphorus Pentaoxide

• Another Example is N3O5.

This would be called Trinitrogen Pentaoxide

Using “Mono” with Covalent Molecules

• When there is only one atom of the first element, mono is not used

CO2 is called

Carbon Dioxide not Monocarbon Dioxide

• When there is only one atom of the second element, mono is used.

N2O is called

Dinitrogen Monoxide

Counting Atoms

Three Laws of Chemistry

There are three guiding principles in the study of chemistry.

1) The law of conservation of mass2) The law of constant composition3) The law of conservation of energy

The law that we need to know for studying chemical reactions is the law of conservation of mass.

Law of Conservation of Mass

• This law states that matter can neither be gained nor lost in a chemical reaction.

• In a chemical reaction you have to end up with the same number and type of each atom that you started with.

Calculating The Mass of a Compound

• Find the number of each atoms in a compound.

• Using the periodic table find the mass number of each type of atom in the compound.

• Multiply the mass number by the number of elements in the compound.

MgSO4

Has 1 Mg, 1 S, and 4 O

Mg = 24S = 32O = 16

Mg (24 x 1 = 24)S (32 x 1 = 32)O (16 x 4 = 64) = 120

Calculating Mass of a Compound Examples

• BaCl2 1 Ba and 2 Cl

137 + 2(35) = 207

• CaI2 1 Ca and 2 I

40 + 2(127) = 294

• C6H12O6 6 C and 12 H and 6 O

6(12) + 12(1) + 6(16) = 180

Conservation of Mass in Chemical Equations

• The total mass of the products formed in a chemical reaction must equal the total mass of the reactants.

SiCl4 + 2 H2O Si(OH)2 + 4 HCl

1.00g ? 2.20g 1.90g

2.20 + 1.90 = 4.10

4.10 – 1.00 = 3.10

3.10 is how much H2O there is in the equation

Another Conservation of Mass Example

• FeSO4 + 2 KI FeI2 + K2SO4

2.95 3.21 5.40 ?

2.95 + 3.21 = 6.16

6.16 – 5.40 = 0.76

There is 0.76 g of K2SO4

Chemical Equations

• A chemical equation gives an outline of what is happening in a chemical reaction.

• The substances on the left hand side are the reactants.

• The substances on the right hand side are the products.

Keeping Both Sides Equal

• In the top pictures, the number of atoms are not equal on both sides and that can not happen in an equation.

• In the bottom picture, the same number and types of atoms appear on both sides.

Rules for Balancing Equations

1) Adjust the numbers of each kind of atom by changing the big numbers in front of the formulas of the compounds and elements. These are called the coefficients.

2) Never change the small numbers in the formulas. These are called the subscripts and are part of the formula.

3) Use pencil because you may have to change coefficients several times

4) No need to include “1” as a coefficient.

Helpful Suggestions for Balancing Equations

• Tally up how many of each type of element there is on each side of the equation.

• Work on one thing at a time.• Look for polyatomic ions or elements that

appear only once on each side. Balance those first.

• If you have difficulty balancing an element, leave it and come back to it at the end.

• Leave H2, N2, O2, F2, Cl2, Br2, and I2 to balance at the end.

Balancing Equations Example

• Na + Cl2 NaCl

Another Balancing Equation Example

• C + O2 CO

Yet Another Balancing Equation Example

• KI + Pb(NO3)2 PbI2 + K(NO3)

Writing and Balancing Equations

• You need to have your periodic table handy.• You also need your reference sheet handy.

• You will read a sentence and make up a skeleton equation.

• And then you will balance the skeleton equation!

Two handy hints!

• If an element is by itself it has no charge» Sodium metal is just Na» Magnesium is just Mg» Gold is just Au

• If one of the following is written in the sentence by itself, it comes in a pair (diatomic)

» Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine and Astatine

» H2 N2 O2 F2 Cl2 Br2 I2 At2

Example 1

• Sodium and Fluorine react to form Sodium Fluoride

Example 2

• Sodium Chloride and Silver (I) Nitrate react to form Sodium Nitrate and Silver (I) Chloride

Example 3

• Aluminum metal and Copper (II) Chloride react to form Aluminum Chloride and Copper metal

Example 4

• Beryllium Oxide and Carbon Dioxide react to form Beryllium Carbonate

Example 5

• Sodium Oxide and Carbon Dioxide react to form Sodium Carbonate

Example 6

• Potassium Chlorate reacts to form Potassium Chloride and Oxygen gas (hint!)

Example 7

• Potassium oxide and water react to form potassium hydroxide

Example 8

• Chlorine gas and Sodium Bromide react to form Sodium Chloride and Bromine gas

Example 9

• Magnesium metal and Hydrogen Chloride react to form Magnesium Chloride and Water

Example 10

• Sodium Carbonate and Calcium Chloride react to form Sodium Chloride and Calcium Carbonate

Example 11

• Zinc (II) Carbonate reacts to form Zinc (II) Oxide and Carbon Dioxide

Information Gained from Chemical Reaction

• It is sometimes useful to know the state of a compound in a given chemical reaction. This information is given in the form of a subscript in parentheses after the formula.

• (s) is solid

(l) is liquid

(g) is gas

(aq) is aqueous

(dissolved in water)

(ppt) is precipitate

(solid in a liquid)

Types of Chemical Reactions

• There are five basic types of chemical reactions:– Synthesis– Decomposition– Single Replacement– Double Replacement– Combustion

Synthesis Reactions

• Synthesis reactions happen when two or more substances combine to form one compound.

A + B AB

2 Na + Cl2 2 NaCl

Al + P AlP

Decomposition Reactions

• Decomposition Reactions happen when one substance breaks down into two or more simpler substances.

• AB A + B

• CaF2 Ca + F2

• 2 Fe2O3 4 Fe + 3 O2

Single Replacement Reactions

• Single Replacement reactions happen when one element is replaced by another in a compound

• A + BC AC + B

• Zn + CuCl ZnCl + Cu

• MgO + Ca Mg + CaO

Double Replacement Reactions

• Double Replacement reactions happen when two elements in a reaction exchange places with each other.

• AB + CD AD + CB

• PbCl + KBr PbBr + KCl

• HCl+Ca(OH)2H(OH)+CaCl2

Combustion Reactions

• Combustion Reactions involve the burning (O2) of a hydrocarbon to form carbon dioxide and water.

• CXHY + O2 CO2 + H2O

• 2C2H6+7O24CO2 + 6H2O

• 2CH4 + 4O2 2CO2 + 4H2O

Acids and Bases

And neutralization reactions

Acids

• Substances that release hydrogen ions (H+) when mixed in water

• Physical Properties:– Sour tasting– Wet to the touch when in solution– Water soluble– Good conductors of electricity, therefore

electrolytes

Acids

• Chemical Properties– React with metals to produce hydrogen

gas– Corrosive– Make chemical indicators change colour– React with bases to produce a neutral

solution

Acids

• Examples:

Bases

• Substances that release hydroxide ions (OH-) when mixed in water. Also called alkaline

• Physical Properties:– Bitter tasting– Slippery to the touch when in solution– Water soluble– Good conductors of electricity, therefore

electrolytes

Bases

• Chemical Properties– Corrosive– Make chemical indicators change colour– React with acids to produce a neutral

solution

Bases

• Examples:

Chemical Indicators

• Are solutions that change colour in acids and in bases

• Can be either – natural or – synthetic

Chemical Indicators

• Litmus paper:– Base turns it Blue!– Acid turns it Red!

Universal Indicator is a mixture of chemicals that changes colour through a wide range of pH values

The pH scale• A numerical scale used to show how

acidic or basic a solution is

• pH stands for “power of hydrogen”

The pH scale• pH is a logarithmic scale which means

that every unit on the scale represents a tenfold (10X) effect on the concentration of the solution

The pH scale: Logarithmic• This means that pH 3 is 10 times more acidic than ph 4. • If the value changes by more than one number you

must multiply – ex. From pH 5 to pH 8 = 10 x 10 x 10 (3 steps = 10

multiplied by itself 3 times)

Naming Acids

• A binary acid forms when an H+ bonds with a non-metal

• HF (aq), HCl (aq), HBr (aq), HI (aq), H2S (aq), and H3P (aq) are some common binary acids

• To name them, use the following structure:– “hydro + ______ ic acid”

Naming Acids

• An oxyacid has a non-metal and an oxygen component

• H3PO4, HClO3, HIO3, H2SO4, HBrO3, H2CO3, and HNO3 are some common oxyacids

• To name them:– “_____________ ic acid”

Naming Bases

1. Name the metal

2. Name the polyatomic (i.e. hydroxide)

• Example– Mg(OH)2 – magnesium hydroxide

Neutralization Reactions• A type of double displacement reaction

• Acid + Base Water + Salt

• A salt is an ionic compound. The pH of the products is around 7 (neutral)

Example

hydrochloric acid + sodium hydroxide water + sodium chloride

Practise!!

• Try the practise questions on your worksheet!