Chemistry grade 11

Chemistry
Exam Review
Matter and Chemical Bonding
Significant Digits
All non zero integers are significant ~ 456cm
All zeros to the left of the first non zero digit are not significant~ 0.005kg
All zeros between non zero digits are significant~ 207.08 km
All zeros at the end of a number that has a decimal point are significant ~ 34.070 mg
Density
Density is a physical property of matter, as each element and compound has a unique density associated with it. Density defined in a qualitative manner as the measure of the relative "heaviness" of objects with a constant volume.

Pure Substances
A substance with uniform composition. Cannot be separated by physical or mechanical means.
Elements
Cannot be broken down or changed into another substance using chemical means. *Building blocks of matter*
Compounds
A pure substance that is composed of two or more elements chemically combines in fixed proportions
Mixtures
A combination of two or more kinds of matter, in which each component retains its own characteristics
Heterogeneous
A mixture in which the different components can be distinctly seen
Homogeneous
A mixture in which the different components are mixed so that they appear to be a single substance; a solution
Physical Properties
Chemical Properties
Qualitative
Quantitative
Reactivity with water
Reactivity with air
Reactivity with pure oxygen
Reactivity with acids
Reactivity with pure substances
Combustibility (flammability)
Toxicity
Decomposition
Physical State
Colour
Odour
Crystal shape
Malleability
Ductility
Hardness
Brittleness
Melting point
Boiling point
Density
Solubility
Electrical Conductivity
Thermal Conductivity

Accuracy
Refers to how close a given quantity is to an accepted or expected value
Precision
Refers to the exactness of a measurement or the closeness of a series of data points
Atomic Theory of Matter
John Dalton described atoms as solid, indestructible particles that make up all matter.
All matter is made up of tiny particles called atoms. An atom cannot be created, destroyed or divided into smaller pieces.
The atoms of one element cannot be converted into the atoms of any other elements
All the atoms of one element have the same properties such as mass and size. These properties are different from the properties of the atoms of any other element.
Atoms of different elements combine in specific proportions to form compounds

Mass number = number of protons + number of neutrons
Atomic number = number of protons
Isotopes
Atoms of an element that have the same number of protons but different numbers of neutrons
Periodic Table Trends

Types of Chemical Bonds
Ionic Bond : formed when one atom accepts or donates one of its valence electrons to another atom
Covalent Bond: formed when atoms share valence electrons. The atoms do not always share electrons equally, so a polar covalent bond may result.
Metallic Bond: when electrons are shared equally by two metallic atoms. The electrons that participate in metallic bonds may be shared between any of the metal atoms in the region.
If the electronegativity values of two atoms are:
Characteristics of Metallic Bonds:
Heat conductivity (mobile electrons can carry the kinetic energy of heat),
Shiny appearance (the rapidly moving electrons emit energy in the form of light),
Electricity conductors (electricity is the flow of electrons), and
Malleability (ability to be easily shaped into flat sheets or drawn into wires). similar... Metallic bonds form between two metal atoms.
Covalent bonds form between two non-metal atoms.
Non polar covalent bonds form when the electronegativity values are very similar.
Polar covalent bonds form when the electronegativity values are a little further apart. different... Ionic bonds are formed.

Properties of Ionic and Covalent Compounds
Property
Ionic Compound
Covalent Compound
State at room temperature
Crystalline solid
Liquid, gas, solid
Melting point
High
Low
Electrical conductivity as a liquid
Yes
No
Solubility in Water
Most have high solubility
Most have low solubility
Conducts electricity when dissolved in water
Yes
Not usually

http://www.youtube.com/watch?v=CGA8sRwqIFg
Octet Rule
Atoms bond in order to achieve an electron configuration that is the same as the electron configuration of a noble gas. When two atoms or ions have the same electron configuration they are said to be isoelectronic with on another.
Polar Molecules and Shapes
When two bonding atoms have an electronegativity difference that is greater than 0.5 but less than 1.7 they are called polar covalent bond. Since the electronegativity of the elements are not equal one will have the larger EN value and therefore more attraction. This gives that element a partial negative charge. The less attractive element will have a partial positive.
*when drawing shapes and diagrams remember to add partial charges and vector arrows

Linear

Bent

Pyramidal

Tetrahedral

Chemical Formulas
A chemical formula provides two pieces of information:
1. The elements that make up the compound
2. The number of atoms of each element that are present in a compound
Chemical Nomenclature is a system used in chemistry for naming compounds
Binary Ionic Compounds the cation is named first, anion second. If the metal (Cation) has multiple oxidation states write the oxidation state in roman numerals~ Copper (II), Copper (I)
Alternatively the oxidation state can be indicated by changing the end of the metal's name to "ic" or "ous" and using the Latin name of the element.
"ic" indicates the larger valence number
"ous" indicates the smaller or lower valence number
~ Tin (IV) Stannic, Tin (II) Stannous
The non metal is named with the ending changed to "ide"
Naming Compounds that Contain Hydrogen
When hydrogen acts like a action it is called hydrogen
When hydrogen acts like an anion it is called hydride
Polyatomic Ions
The polyatomic ion has an ending of "ate" when it is in its most common form
If there is one less oxygen than the ending is changed to "ite"
If there are two less oxyggen atoms then there is a prefix "hypo" and the ending is still "ite"
If there is one more oxygen atom, than originally then the prefix changes to "per" and ending is "ate"
Naming of a compound with two non-metals...Molecular/ Covalent
1. Each metal has a prefix that represents the number of atoms or mono hept di oct tri non tetra dec penta hexa
2. The stock system is used where the roman numerals are placed in brackets to represent the charge of the first non metal
Naming and Writing chemical formulas for acids and bases
Acids can be classified into two main groups, binary acids and oxoacids
Binary Acids contain 2 elements, Hydrogen and a non metal
Naming of binary acids – 2 methods: Classical Method IUPAC method -prefix hydro -aqueous -root – non metal name -hydrogen non metal “ide” ending -ending – “ic acid”

Oxoacids, aka Oxy acids – 2 methods:

Classical Method IUPAC method -root of anion (polyatomic ion) -aqueous -replace “ate” with “ic acid” -hydrogen name of polyatomic ion -replace “ite” with “ous acid” -replace “hypo__ite” with “hypo__ous acid” -replace “per__ate” with “per___ic acid”

Naming Bases is the same as naming a metal bonded to a hydroxide ion.

Zero Sum Rule
The charges (atoms) are multiplied to get an overall charge of zero
(Charge of cation)(#atoms) + (Charge of anion)(#atoms) = 0
Criss Cross Rule
Cross the charges of the elements and bring down as the sign
Types of Reactions
Synthesis
2 or more elements combine to form a single compound. ~ A + B  C
Decomposition
Is the reverse to a synthesis reaction. A compound breaks down into elements or other compounds ~ C  A + B
Single Displacement
~ AB + C  AC + B
Double Displacement
~ AB + CD  AD + CB
Combustion
Reactions of a compound or element with oxygen gas to form the most common oxides of the elements that make up that compound.
*There are 2 types of combustion reactions; complete and incomplete combustion
*Complete combustion: *the reaction is very clean, no residue is produces. *energy, blue fame ex. CH4 + O2  CO2 (g) + H2O (g)

*Incomplete combustion: *the reaction is very dirty, residue is produced *Orange flame, camp fire ex. CH4 + O2  C (s) + CO (g) + CO2 + H2O

Note: heat and light are also produced in both these types of reactions

Chemical Quantities
Isotopic Abundance: The relative amount in which each isotope is present in an element
Average Atomic Mass: the average if the masses of all the elements isotopes
Weighted Average

Calculating Average Atomic Mass

Avogadro's Constant (NA)
Equal to one mole. 6.022 x 1023
Mole (mol) (n)
The amount of substance that contains as many elementary entities. One mole contains 6.022 x 1023
~N = number of particles

Molar Mass
To find the molar mass of an element add all the masses of each element it contains

Percent Composition from Formula and from percent
Relative mass of each element in a compound.
Ex. Mass percent of Zn =
Ex. Mass percent of Hg in HgS =

Empirical Formulae & Molecular Formulae

Molecular Formula of a Hydrate
A hydrate is a compound that has a specific number of water molecules bound to each formula unit.
Ex. You need to calculate the percent by mass of water in the hydrate of barium hydroxide. You need to determine how many water molecules are bounded to each formula unit of Ba(OH)2 (s) to form the hydrate.
Step 1. Find the amount in moles of barium hydroxide in the sample. Then find the amount in moles of water in the sample.
Step 2. Divide both mole amounts by the smallest mole.
The numbers that are calculated in the end will be the coefficients of Ba(OH)2 H2O
Stoichiometry (mole ratios) http://www.youtube.com/watch?v=SjQG3rKSZUQ Limiting Reagent/Reactant http://www.youtube.com/watch?v=rESzyhPOJ7I Percent Yield http://www.youtube.com/watch?v=Kk5kZO8ueWI Unit Four, Solutions and Solubility
Solubility Terms
Word
Definition
Solution
A homogeneous mixture of two or more substances
Solvent
The component of a solution that is present in the greatest amount

Solute
A substance that is dissolved in a solution

Homogeneous Mixture
A mixture that has uniform composition

Heterogeneous Mixture made up by two or more different solutions which are mixed but not combined

Variable Composition
When the makeup of a mixture can vary or contain different properties

Aqueous Solution
A solution involving water

Miscible
Two substances, that when mixed, produce a homogeneous mixture
Immiscible
Not forming a homogeneous mixture when two or more substances are added together
Alloys
A metal made by combining two or more metals
Solubility
The ease with which a solid or gas dissolves in a liquid
Soluble
Able to dissolve (especially in water)
Insoluble
Incapable of being dissolved
Sparingly/Slightly Soluble
Substances in between soluble and insoluble
Saturated Solution
Solution which no more of the solute can be added to the solvent
Unsaturated Solution
The solute concentration is lower than its equilibrium solubility
Supersaturated Solution
A solution that contains more of the dissolved material than could be dissolved by the solvent under normal conditions
Concentration
The amount of solute per quantity of solvent

Endothermic Process
Exothermic Process
Requires a continual supply of energy
No
Yes
Absorbs Energy
No
Yes
Has Energy as a Product
No
Yes
Occurs best at....
Low Temperatures
High Temperatures

A Solution forms when... “The forces of attraction between the solute and the solvent are greater than the forces of attraction within the solvent or solute itself”
If intramolecular forces are stronger than Intermolecular forces...no solution forms
If intermolecular forces are stronger than intramolecular forces...a solution will form
Like Dissolves Like Rule ~Substances of the same type will be soluble within each other. i.e. Polar substances will be soluble in polar solvents and Non polar substances will be soluble in Non polar solvents
Intermolecular Forces
Dipole-Dipole
Exists between two polar molecules
Hydrogen Bonding
A special case of increased dipole-dipole
~ Occurs with molecules that contain, O-H, N-H and F-H
O, N and F
These atoms are highly electronegative and have a small atomic radius,
~ these bonds are very polar and the interaction between these molecules are very strong – greater than dipole-dipole
Ion-Dipole
Occurs between an ionic compound and a polar molecule
Exception – insoluble ionic compounds have stronger attraction with themselves than with the solvent
2 Factors must be considered with ionic compounds:
Ion Charge: the greater the charge, the greater the attraction and therefore the lower the solubility
Ion Size: the smaller the ion, the lower the solubility

~ As the non polar region increases the solubility in polar solvents will decrease, the solubility in non polar solvents will increase
Ex. Methanol, CH3OH Ethanol, CH3CH2OH Propanol, CH3CH2CH2OH
Non polar
Polar
Predicting Solubility 0 0.4 1.7 3.0

Other Factors that Affect Solubility
Temperatures
Solid
Energy is required to break the bonds within ~ as temperature increase, solubility increases

Liquid
Bonds are not very strong ~ temperature has no affect

Gas
Gases have a lot of kinetic energy that is lost as a gas is dissolved ; as temperature increases, the gas regains that energy ~ as temperature increases the solubility decreases
Pressure
Solid
No affect

Liquid
No affect

Gas
The solubility of a gas is directly related to the pressure above the liquid ~ as the pressure increases the solubility of a gas will increase

Net Ionc Equations and Qualitative Analysis
Ionic Equation ~ a chemical equation in which soluble ionic substances are written in dissociated form
Net Equation ~ an ionic equation that does not include spectator ions
Spectator Ion ~ an ion that is present in a solution but is not involved in the creation
Precipitate ~ a insoluble product in a reaction
Qualitative Analysis~ a type of analysis that identifies the elements, ions or compounds in a sample
a) Flame Test b) Colour of Solution c) Formation of Precipitate
Flame Test ~ a clean chromium wire is dipped in the solution and placed into a flame, the colour of the flame indicates the presence of a specific ion
Colour of the Solution~ aqueous solutions of ionic compounds of certain cations and anions also have characteristic colours
Precipitate Reaction ~ adding a known reactant to a solution and observing if a precipitate forms can help determine the elements that are in the solution.
Acids and Bases http://www.youtube.com/watch?v=vShCnTY1-T0 Acids and Bases Chart
Property
Acids
Bases
Taste
Sour
Bitter
Texture
No characteristic texture
Slippery to the touch
Conductivity in Aqueous Solution
Conduct electricity
Conduct electricity pH Less than 7
Greater than 7
Litmus Paper
Red
Blue
Phenolphthalein
Colourless
Pink
Corrosion
Corrode tissues and metals
Corrodes tissues but not metals
Reaction with Metals
React with active metals to produce H2
React with carbonates to produce CO2
No Reaction

No Reaction
Reaction with Carbonates
Citrus fruits, vinegar, carbonated drinks, vitamins
Soap, baking soda, oven cleaner, household ammonia

Arrhenius Theory on Acids and Bases:
~ An acid is a substance that dissociates in water
Acids – H+ Bases – OH-
Four Limitations
*H3O+ can’t explain the formation
*Ammonia, NH3 is basic
*Only solvent, H2O
*Salt of carbonates, dissolved in H2O it produces a basic solution but it does not contain OH-
Bronsted-Lowry Theory of Acids and Bases:
~Acid- H+ ions can be removed
~Base – Substances that can remove a proton
Strong Acid~ an acid that completely ionizes or dissociates Strong binary acids include HCL, HBR and HF Strong Oxyacids include HNO3, HClO4 and H2SO4
Strong Base~ a base that completely dissociates Strong bases include all elements from group 1 and group 2 except beryllium
Weak acids and Weak bases~ do not completely ionize http://www.youtube.com/watch?v=AlJOxy1DdQk How to Make a Solution
1) Mass out______of the Solid
2) Add mass to Volumetric flask
3) Add distilled water to the __L mark
4) Shake
Conjugate Bases and Conjugate Acids http://www.youtube.com/watch?v=0LM6wPpypxM Titration
~ a quantitative analysis to determine the concentration of an unknown solution
In a titration the solution with the known concentration (called the standard) is added to a solution with an unknown concentration but a known volume
Once the titration is completed, the volume of the standard required to neutralize the unknown is determined and the concentration of the unknown can be calculated Equivalence Point~ is reached when the number of hydrogen atoms (moles of hydrogen) equal the number of hydroxide atoms (moles of hydroxide) the solution is considered neutral End Point~ The point in which the indicator changes colour, indicating the solution is neutral http://www.youtube.com/watch?v=XjFNmfLv9_Q Dilution Questions http://www.youtube.com/watch?v=v6dnEp58mVk Equations:

Unit Five, Gases and Atmospheric Chemistry
Particle Theory of Matter
Matter is made up of tiny particles...particles refer to atoms, ions or molecules
Particles of matter are in constant motion
Particles of matter are held together by strong electric forces
There are empty spaces between the particles of matter that are very large compared to the particles themselves
Each substance has unique particles of matter that are different from the particles of other substances
\Temperature affects the speed of the particles..higher T, the faster the speed of the particles
Kinetic Molecular Theory of Gases
A gas is composed of particles in constant motion.
The average kinetic energy depends on temperature, the higher the temperature, the higher the kinetic energy and the faster the particles are moving.
Compared to the space through which they travel, the particles that make up the gas are so small that their volume can be ignored.
The individual particles are neither attracted to one another nor do they repel one another.
When particles collide with one another (or the walls of the container) they bounce rather than stick. These collisions are elastic; if one particle gains kinetic energy another loses kinetic energy so that the average remains constant.
Gas Pressure
Pressure is defined as the force that is exerted on an object per unit of surface area.
Pressure (kPa) = force (N) / area (m2)
A gas will exert pressure on the walls of the container the gas occupies
Atmospheric Pressure and Units
Earth's pressure at sea level is 101.3kPa, it changes due to weather. A Barometer measures atmospheric pressure.
Units: 760mmHg = 760 torr = 1 atm = 101.3 kPa
Boyle's Law
States that the volume at a given amount of gas at constant temperature varies inversely with applied pressure.
P1V1=P2V2
Kelvin Scale
Charles Graphed his results of V vs T and extrapolated his graph and determined that a gas has 0 volume at -273.
-237=0 K....absolute zero
To go from temperature in Kelvin add 273 to go to temperature in Celsius minus 273

Charles Law
The volume of a fixed mass of a gas is proportional to its temperature (in Kelvin) when pressure is kept constant.

Gay Lussac's
States that the pressure of a fixed amount of gas is directly proportional to its T in Kelvin.

Combined Gas Law
Combines Boyle's, Charles' and Lussac's laws...

STP and SATP
STP:
Temperature: 0 ~ 273 K
Pressure: 101.3 kPa
SATP:
Temperature: 25 ~ 298 K
Pressure: 101.3 kPa
Dalton's Law of Partial Pressures

Avogadro's Law
Equal volumes of all ideal gases at the same temperature and pressure contain the same number of molecules

Therefore, 1 mol of any gas occupies the same volume at the same T and P, assuming the volume of the gas molecule itself is negligible. Remember, the mass of 1 mol of gas is unique the volume is the same.

Ideal Gas Law
PV = nRT
R (constant) = 8.314 kPa x L/ mol x K
Dalton's Law of Partial Pressures:
The total pressure of a mixture of gases is the sum of the individual pressures of each gas

Molar Volume
(L/mol) = V/n

Including water vapour pressure in gas Calculations
*When collecting gases by bubbling them through a water (displacement method), the pressure of the actual gas must be adjusted to take into account the pressure of the water vapour.
*In a sealed container (closed system) water molecules at the surface evaporate forming water vapour or gas phase water molecules. This causes an additional gas P called water vapour P. As T increases the solubility of gases in solution decreases, therefore more water molecules will become vapour, therefore water vapour P increases. Water vapour P changes with respect to T.
PH2O vapour @ 20 C = 2.34 kPa
PH2O vapour @ 25 C = 3.17 kPa
PH2O vapour @ 30 C = 4.24 kPa

When calculating volume of gas produced when collecting over water, the P of water vapour must be subtracted…"dry" gas