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117 Cards in this Set
- Front
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Physical Property |
A description or characteristic of a substance that does not involve forming a new substance. For example: colour, texture, density, smell, solubility, taste, melting point, and physical state. |
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Chemical Property |
A characteristic behaviour that occurs when the substance changes into something new. For example: A chemical property of hydrogen peroxide is that it bleaches colour substances. |
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Examples of Chemical Properties (Reference) |
*Refer to pg. 175 Reaction of an acid with a base: Vinegar reacts with baking soda to produce carbon dioxide gas. Flammability: Gasoline burns easily if ignited. Bleaching Ability: Hydrogen peroxide breaks down the pigment (colour) in hair. Corrosion: Discarded batteries in landfill sites break down readily when they come in contact with groundwater. |
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Physical Change |
A change that does not produce a new substance. Includes: Changes of state (melting, evaporation, condensation, sublimation, and dissolving) *Many physical changes can be reversed* |
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Chemical Change |
The change that a substance goes through to produce a new substance (or more than one new substance). Possible Evidence of Chemical Change: - A new colour appears - Heat or light is produced or absorbed - Bubbles of gas are formed - A solid material (a precipitate) forms in a liquid - The change is (generall) difficult to reverse *Many chemical changes cannot be reversed* |
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WHMIS |
Workplace Hazardous Material Information System - Provides workers with information on the safe use of hazardous products in their workplace - Employers must, by law, provide this information Consists of: - WHMIS product labels - Materials safety data sheets (MSDS) - Worker training |
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WHMIS product labels |
Supplier Label: Required on any hazardous material that is sold or imported to a workplace in Canada (in both English and French) Consists of: - Name of product - Information on safe handling - Any relevant hazard symbol - The supplier's contact information - A reference to the MSDS |
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MSDS: Materials Safety Data Sheet |
For more detail, use the materials safety data sheet that comes with the product. Includes information about: - Any hazardouz properties - Safe handling - Storage procedures - What to do in an emergency |
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Worker Training |
Training that helps everyone understand the hazards within their workplace. - The people who frequently work with hazardous products must have special training. |
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Elements |
A pure substance that cannot be broken down into simpler substance. |
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Periodic Table |
A powerful tool that chemists use to explain and predict the properties of the elements. - The elements of the periodic table can be classified as metals, non-metals and metalloids. |
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Metals |
Example: Nickel (Ni) State at room temperature: Solid Lustre: Shiny Malleability: Generally malleable Electrical Conductivity: Conductors |
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Non-Metals |
Example: Bromine (Br) State at room temperature: Solid, liquid, or gas Lustre: Dull Malleability: Brittle (if solid) Electrical Conductivity: Insulators |
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Hydrogen (Exception) |
Hydrogen has some properties in common with the metals in the first column. However, it lacks many of the chracteristic physical properties of metals at room temperature. - Hydrogen is grouped on its own. |
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Rows and Columns on the Periodic Table |
Each row of elements on the periodic table is called a period. (A total of 7 periods) Each column is called a group or family of elements. (A total of 18 groups) *Each group/family of elements have similar properties. |
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Group 1 on the Periodic Table |
ALKALI METALS The elements (except hydrogen) in the first column of the periodic table (Group 1) - These elements are soft, highly reactive metals. Forms ions with a single positive charge. |
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Group 2 on the Periodic Table |
ALKALINE EARTH METALS The elements in the second column of the periodic table (Group 2) *Check Presentation for Characteristics* |
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Group 17 on the Periodic Table |
HALOGENS The elements in the seventeenth column of the periodic table (Group 17) - One of the most reactive groups on the periodic table. Forms ions with a single negative charge. |
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Group 18 on the Periodic Table |
NOBLE GASES The elements in the eighteenth column of the periodic table (Group 18) - They are so stable that they rarely react with any other chemicals. |
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Atomic Structure (Mass & Volume) |
A simple model of the atom that explains the properties of elements. - Most of the mass of the atom is concentrated in an extremely small, dense, positively charged core called the nucleus. - Most of the atom's volume is empty space. |
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Mass Number |
The total number of protons and neutrons. |
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Subatomic Particles |
1. Proton; positive electrical charge; symbol of p+ ("+" superscript); location nucleus. 2. Neutron; neutral electrical charge; symbol of n0 ("zero" superscript); location nucleus. 3. Electron; negative electrical charge; symbol of e- ("-" superscript); location orbit around the nucleus. |
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Atomic Number (Periodic Table Organization) |
The number of protons in the nucleus is called the atomic number of the element. For example: Carbon contains six protons in its nucleus, so, its atomic number is 6. The elements of the periodic table are arranged in order of increasing atomic number. |
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Electrical Charge of Atoms |
Atoms are electrically neutral; with equal numbers of protons and electrons. |
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Bohr-Rutherford Diagram |
A useful way of representing the arrangement of electrons around the nucleus for the first 20 elements. - Each electron orbit is shown as a ring around the nucleus 1st orbit: Max. 2 eletrons 2nd orbit: Max. 8 electrons 3rd orbit: Max. 8 electrons Elements with atomic numbers above 18 must have electrons in the fourth orbit. Remember: This is only a model of the atom. The actual behaviour of electrons is much more complicated. |
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Isotopes |
The same element that contains the equal number of protons but has a different number of neutrons in the nucleus. - Li-7 = Lithium has a mass number of 7. |
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Electron Arrangements and Reactivity |
The outer electrons of an element are responsible for the element's reactivity. The alkali metals are known for their reactivity. Alkali metals only contain one electron in its outer orbit. The noble gases are known for their stability. Noble gases all have completely filled outer orbits. Therefore, we believe that there is a stable quality about full outer shells. |
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Compounds |
Compounds are substances made up of two or more elements in a fixed ratio. - Electrons are important to understanding how elements combine to form compounds. |
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Ion (in comparison to atoms) |
An atom is an electrically neutral particle with an equal number of electrons and protons. An ion is an atom that has become charged by gaining or losing electrons. For example: Sodium atoms lose one electron when they react with other atoms. Each resulting sodium ion contains 11 protons and only 10 electrons. Therefore, the sodium ion has a ionic charge of +1. Na+ ("+" superscript) |
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How distance from the nucleus affects the electrons |
The farthest electron is least tightly held to the nucleus. |
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Cations |
Ions with a positive charge. Cat: It is paws-itive! Naming Rule: The same as the name of the element. Sodium forms sodium ions. |
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Anions |
Ions with a negative charge. Naming Rule: Add "ide" to the stem of the name. Oxygen forms oxide ions. Phosphorus forms phosphide ions. |
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Ionic Compounds |
An ionic compound is a compound made up of one or more positive ions (cations ~ in our case, metal) and one or more negative ions (anions ~ in our case, non-metal). - Non-metal takes electrons from the metal atoms - Metal gives electrons to the non-metal The positive and negative ions from different elements attract to each other to form compounds. The attraction that holds oppositely charged ions together in a compound is called an ionic bond. |
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Why does electron transfer occur to create ions? |
- The metal's hold on its outer electrons is weak - The attraction of the non-metal for the metal's electron is strong - A full outer electron orbit is very stable |
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Ionic Crystal |
Ions sometimes joins together to form an ionic crystal. - Consists of alternating metal and non-metal ions, extending in three dimensions. Example (Sodium Chloride) There is no individual "NaCl" particle: the compound always consists of many sodium ions and chloride ions held together in a crystal. |
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Ionic Compounds in Water |
Some ionic compounds are soluble in water. When they dissolve, they separate into ions. Water molecules surround each ion as it leaves the crystal. The positive and negative ions are pulled away from the crystal by water molecules. The water molecules arrange themselves around ions in a particular way: the oxygen atoms of water molecules are attracted to positive ions. The hydrogen atoms are attracted to the negative ions. *For visual: Page 193 |
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Difference between Molecule and Compound |
Answers Differ ~ Check Textbook |
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More Complex Ionic Compounds |
Example: Aluminum can also react with chlorine gas. However, each aluminum atom has three electrons to lose, while each chlorine atom can only take 1 electron. How can this be resolved? Each aluminum atom reacts with three chlorine atoms. Therefore: AlCl3 |
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Properties of Ionic Compounds |
Due to the strength of the ionic bond: ionic compounds are hard, brittle solids with high melting points. Most ionic compounds are also electrolytes, which means that they dissolve in water to produce a solution that conducts electricity. The presence of these ions improves the electrical conductivity because they can carry charges (electric current and/or movement of electrons) faster through the solution. Pure water: Poor conductor of electricity Tap water, lake water and seawater: Better conductors (because they contain ions from a variety of sources, such as minerals. |
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Naming Ionic Compounds |
There is a systematic method of naming chemicals; "The International Union of Pure and Applied Chemistry" (IUPAC) is the organization that decides how chemicals will be named. The name of the metal ion remains the same but the ending of the name of the second ion - the non-metal - changes to "ide". Examples: Magnesium and Chlorine = Magnesium Chloride Aluminum and Oxygen = Aluminum Oxide |
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Writing Chemical Formulas for Ionic Compounds |
1. Figure out the ionic charge of each ion. Ex: (+3) (-2) Al O 2. Determine how many ions of each type are required to bring the total charge to zero (the sum of all charges in the compound must equal zero) Ex: 2(+3) + 3(-2) = 0 Al Cl Therefore, the chemical formula of aluminum oxide is Al2O3. |
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Crisscross Method for Determining Formulas |
1. Write the symbols of the elements and their ionic charges. Ex: (+3) (-2) Al O 2. Crisscross the numbers of the ionic charges so that they now become subscripts. Al2O3 *Beware: The chemical formula of an ionic compound is always the simplest possible ratio of the ions. For example, Al3N3 must be simplifies to AlN. |
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Elements with Multiple Ionic Charges (A.K.A Multivalent Ions) ~ Naming Rule |
Some metals have 2 stable cations. Ex: Copper (Cu) Cu+ or Cu2+ ("2+" superscript) Copper (I) ion Copper (II) ion Tin (Sn) Sn2+ ("2+" superscript) Tin (II) ion or Sn4+ ("4+" superscript) Tin (IV) ion |
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Naming Compounds Involving Elements with Multiple Ionic Charges |
1. Determine the ionic charge of the metal so that you can include it in the name. Ex: FeCl2 is called Iron (II) Chloride because the ionic charge of iron is +2. FeCl3 is called Iron (III) Chloride because the ionic charge of iron is +3. |
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Polyatomic Ions |
A polyatomic ion is an ion that consists of a stable group of several atoms acting together as a single charged particle. - The ionic charge of a polyatomic ion is shared over the entire ion rather than being on just one atom. |
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Common Polyatomic Ions |
*At our level: All polyatomic ions are anions expect ammonium. *Page 202* Nitrate Ion: NO3 (Charge: -1) Nitrite Ion: NO2 (Charge: -1) Hydroxide Ion: OH (Charge: -1) Hydrogen Carbonate Ion (also called Bicarbonate Ion): HCO3 (Charge: -1) Chlorate Ion: ClO3 (Charge: -1) Carbonate Ion: CO3 (Charge: -2) Sulfate (or Sulphate) Ion: SO4 (Charge: -2) Phosphate Ion: PO4 (Charge: -3) Ammonium: NH4 (Charge: +1) |
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Naming Compounds Involving Polyatomic Ions |
Use the same steps for naming ionic compounds. The only difference is that the anion is named according to the polyatomic ion rather than the names of the individual elements. Ex: Fe(NO3)3 Iron (III) Nitrate |
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Writing Formulas Involving Polyatomic Ions |
Use the same steps for writing formulas for ionic compounds. *Remember to treat the polyatomic ion as one unit! Practice Answer: Na3PO4 & Cu(NO3)2 *Crisscross method can also be used |
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Molecular Compound (Or Covalent Compound) |
Molecular compounds are made up of individual particles called molecules. The elements that make up molecular compounds are all non-metal. Examples: Sugars, fats and proteins. Water - H2O Sugar - C12H22O11 *Ionic compounds do not exist as individual particles; for they are held together in a crystal. Molecular compounds are not?*check 206* |
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Covalent Bond (Or Molecular Bond) |
Covalent bonds are formed between non-metals; and all non-metals need more electrons. A chemical bond where atoms share electrons. - Can be formed between two identical atoms or between atoms of different elements. |
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Diatomic Molecule |
A molecule consisting of only two atoms of either the same or different elements. Ex: O2 |
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Covalent Bond "Line" Diagram |
For example: H — H, represents a single covalent bond (sharing 1 pair of electrons). O = O (*lines should be the same length as represented above*), represents a double covalent bond (sharing of sharing of 2 pairs of electrons) |
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Common Diatomic Elements |
Hydrogen gas: H2 Oxygen gas: O2 Fluorine gas: F2 Bromine (l): Br2 Iodine (s): I2 Nitrogen gas: N2 Chlorine gas: Cl2 I Never Bring Classwork Home On Friday |
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Naming Molecular Compounds (Without List of Prefixes) Practice: N2O5 & CCl4 |
The prefix is attached to the name of the element to which it refers. However, the prefix mono is used only for the second element in the compound. Practice Answers: N2O5 Dinitrogen Pentoxide CCl4 Carbon Tetrachloride *Remember to use the "ide" suffix *Caution: If the compound contains a metal, then it is an ionic compound and should be named accordingly (with no prefixes). |
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List of Molecular Compound Prefixes |
1 atom: Mon(o)- 2 atoms: Di- 3 atoms: Tri- 4 atoms: Tetra- 5 atoms: Penta- 6 atoms: Hexa- 7 atoms: Hepta- 8 atoms: Octa- 9 atoms: Nona- 10 atoms: Deca- |
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Commonly Known Molecular Compounds |
Many molecular compounds have been known for centuries and have common names that are still in use today. Examples: Water: H2O Ammonia: NH3 Nitric Oxide: NO Hydrogen Sulfide: H2S |
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Writing Chemical Formulas of Molecular Compounds |
1. The prefixes in the name become the subscripts in the formula. Example: Sulfur Dioxide SO2 |
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Molecular Compounds From Fossil Fuels |
Read up on Page 210-211 |
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Chemical Reactions |
In a chemical reaction, one or more substances change into different substances. -One of the most familiar types of chemical reaction is combustion (burning); cooks our food, heats our homes, and allows us to travel. |
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Types of Chemical Reaction Equations |
- Word and Chemical equations are used to describe chemical equations. Word Equations: The names of the reactants and products are written out in full. Chemical Equations: Chemical formulas of the reactants and products are used to represent the chemicals. |
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Chemical Reaction Equations |
Reactants are the substance that are used up during the reaction. Products are the substances that are produced during the reaction. GENERAL FORMAT: Word Equation: iron + sulfur → iron (II) sulfide + energy Chemical Equation: Fe(s) + S(s) → FeS(s) + energy - The arrow is read as "yields," "forms," or "produces." - Substance to the left of the arrow are called reactants. - Substance to the right of the arrow are called products. - "+" signs are placed between the several reactants or products. |
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Stating Symbols in Chemical Equations |
State symbols tell us the state, or form, of each substance in a chemical equation. (s) = solid (l) = liquid (g) = gas (aq) = aqueous (dissolved in water) |
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*Energy in Chemical and Word Equations* |
In situations where the location of the energy (exothermic or endothermic) is not identified, leave "energy" out of the equation. |
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Law of Conservation of Mass |
- Mass is conserved during a chemical reaction; no mass gained and none is lost. "In any given chemical reaction, the total mass of the reactants equals the total mass of the products." During a chemical reaction, the atoms in the reactants are rearranged to form products. Therefore, all the atoms that exist were NOT created or destroyed. |
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Balanced Chemical Equation |
Due to the law of conservation of mass, an equal number of each kind of atom should be on both sides of the equation. Example: H2 (g) + Cl2 (g) → 2HCl (g) *Warning: When balancing equations, use coefficients (they apply to the whole compound). If you individually increase the number of each element, it will turn into a different substances (HO vs. H2O). |
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Skeleton Equation |
A unbalanced chemical equation that indicates the chemicals involved in the chemical reaction. |
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Balancing Chemical Equation Links |
http://education.jlab.org/elementbalancing/ http://www.chemistry-drills.com/index.html https://www.mheducation.ca/school/learningcentres/mod/quiz/attempt.php?id=18866 |
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Types of Reactions: Synthesis |
In the synthesis reactions, two simple reactants combine to make a large or more complex product. General Pattern: A + B → AB Ex: Sodium + Chlorine → Sodium Chloride 2 Na(s) + Cl2(g) → 2 NaCl(s) |
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Types of Reactions: Decomposition
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In decomposition reactions, large compounds are broken down into smaller compounds or elements.
General Pattern: AB → A + B Ex: Water → Hydrogen + Oxygen 2 H2O(l) → 2 H2(g) + O2(g) *Decomposition reactions usually absorb energy |
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Types of Reactions: Single Displacement
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In single displacement reactions, one element displaces or replaces an element in a compound.
General Pattern: A + BC → AC + B Ex: Copper + Silver Nitrate → Copper(II)Nitrate + Silver Cu(s) + 2 AgNO3 (aq) → Cu(NO3)2(aq) + 2 Ag(s) *Single displacement reactions occurs when metals are placed into acids |
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Types of Reactions: Double Displacement
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In double displacement reactions, two elements in different compounds trade places.
AB + CD → AD + CB Ex: Silver Nitrate + Sodium Chloride → Silver Chloride + Sodium Nitrate AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq) |
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Smelter |
The process of heating an ore to high temperatures and collecting the molten metal. |
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Precipitate |
A solid formed from the reaction of two solutions. Many double displacements reactions result in the formation of a precipitate. Some ionic compounds do not dissolve in water; therefore, these insoluble compounds become visible as a precipitate. |
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Combustion |
Combustion is a chemical reaction in which fuel "burns" or reacts with oxygen. The products of this reaction are usually an oxide and energy. |
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Hydrocarbons |
A group of molecular compounds that contain only the elements hydrogen and carbon. - Most hydrocarbons originate from fossil fuels. - The combustion of hydrocarbons powers cars and homes, warms homes, generates electricity and even light up birthday candles. |
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Combustion: Complete Combustion of Hydrocarbons
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If oxygen is plentiful, hydrocarbons burn completely to release the energy they contain. The only products of complete combustion are carbon dioxide and water.
Hydrocarbon + Oxygen → Carbon Dioxide + Water + energy Ex: CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) + energy |
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Combustion: Incomplete Combustion of Hydrocarbons
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If oxygen supply is limited, hydrocarbons burn to release carbon monoxide gas and carbon (soot), in addition to carbon dioxide and water.
*An orange, flickering flame often indicates incomplete combustion. Hydrocarbon + Oxygen → Carbon Dioxide + Water + Carbon Monoxide + Carbon C4H10(g) + 5 O2(g) → 2 CO2(g) + 5 H2O(g) + CO(g) + C(s) + energy |
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Carbon Monoxide and Soot |
* Read up on page 249 |
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Combustion: Combustion of Other Substances (Not Hydrocarbons) |
Element + Oxygen → Oxide + energy Example: Combustion of Magnesium 2 Mg (s) + O2 (g) → 2 MgO (s) + energy |
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Combustion: Hydrogen
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Hydrogen reacts (burns) with oxygen to form water:
2 H2 (g) + O2 (g) → 2 H2O (g) + energy |
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Combustion: Phosphorus
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Phosphorus comes in two forms: white and red phosphorus. P4 (s) + 5 O2 (g) → P4O10 (g) + energy *Read Page 250 in Textbook |
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Corrosion |
Breakdown of a metal as a result of chemical reactions with its environment. |
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Beneficial Corrosion |
When aluminum is exposed to air, it quickly corrodes to form aluminum oxide - one of the hardest substances known. So, the aluminum oxide tightly coats and protects the underlying aluminum metal. Zinc and Copper also form protective coatings when they corrode. - Copper develops an attractive greenish patina after being exposed to the atmosphere for several months. |
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Rust |
Rust is a familiar reddish-brown flaky material produced when metals containing iron corrode. Unlike the corrosion products of aluminum, copper and zinc; rust does not stick well to underlying steel. Instead, rust readily flakes away from the surface of the steel. This process continues until the steel (alloy containing iron) is completely corroded or "eaten away"; leaving a trail of rust flakes! |
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Causes of Rust |
- The presence of air, water, and electrolytes, along with acidity and mechanical stress. OXYGEN & WATER: Steel (alloy containing iron) will not corrode without water and oxygen. *Steel lasts longer in dry climates* ELECTROLYTES: Salt (sodium chloride) is an electrolyte. It doesn't cause corrosion of iron but speeds up corrosion once it starts. So, road salt and saltwater spray off the ocean affect cars and bridges. *CHECK WHY ELECTROLYTES SPEED UP IN BINDER |
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Preventing Corrosion (3 ways) |
Protective Coating - Cover metal with a rust-inhibiting paint, chrome, or plastic coating. Corrosion-Resistant Material - Use materials that do not rust. For example, plastic does not corrode. However, alloys can be made to improve corrosion resistance. *Chromium is used in alloys for surgical-grade stainless steel Galvanizing Galvanized Steel: Steel that has been coated with a thin layer of zinc (protective layer of zinc oxide protects the underlying steel). |
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Properties of Acids |
- Reacts with metals and carbonates - Conducts eletricity - Turns blue litmus paper red - Neutralizes bases - Tastes sour - Act as preservative: harmful microorganisms cannot survive in acid |
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Acid Reaction with Metals |
Acids typically react with metals to produce bubbles of hydrogen gas ("Pop" with burning splint test). Example: Hydrochloric Acid + Zinc → Hydrogen Gas + Zinc Chloride 2 HCl(aq) + Zn(s) → H2(g) + ZnCl2(aq) |
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Acid Reaction with Carbonates |
Acids typically react with carbonate compounds to produce bubbles of carbon dioxide gas. Example: Acetic Acid + Sodium Hydrogen Carbonate → Carbon Dioxide + Water + Sodium Acetate |
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Electrical Conductivity of Acids |
Many acids are good conductors of electricity. However, a solution can conduct electricity only if it contains ions. Unfortunately, acids are molecular compounds; they don't contain ions. Collisions with water molecules break acid molecules apart to from cations (hydrogen ions) and anions. Example: Hydrochloric acid, for example, forms hydrogen ions and chloride ions. HCl(aq) → H+(aq) + Cl-(aq) ("+" and "-" superscript) |
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Acids: Chemical Formulas (When dissolved in water) |
All acids release at least one hydrogen ion when they dissolve in water. Example: HF(aq) → H+(aq) + F-(aq) ("+" and "-" superscript) |
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Naming Binary Acids (Acids that only contain 2 elements) |
- Hydrogen + one other element: HF(aq) - Must use (aq) after the name of an acid; HF without (aq) would technically be Hydrogen Fluoride. To name Hydro"root of other element"ic acid Example: Hydrofluoric acid -Still use ionic charges to get the correct formula (remember the "criss-cross" method) |
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Naming Oxy-Acids (Acids that contain more than 2 elements and are related to polyatomic ions) |
- Hydrogen + more than one other element (usually contains oxygen): HNO3(aq) - Must use (aq) after the name of an acid To name "Root of polyatomic ion"ic acid Example: Nitric Acid -Still use ionic charges to get the correct formula (remember the "criss-cross" method) |
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Naming Oxy-acids (Extended Rules) |
- Only "-ate" polyatomic ions make the "-ic" acids. 1 more oxygen: per______ic acid 1 less oxygen: ______ous acid ("ite")* 2 less oxygen: hypo_____ous acid *Only need to know this for the course Example: H2SO5(aq) = Persulfuric acid H2SO4(aq) = Sulfuric acid H2SO3(aq) = Sulfurous acid H2SO2(aq) = Hyposulfurous acid *Warning: Sulfate is an exception; addition of the letters u & r. |
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Properties of Bases |
- Conducts electricity - Feels slippery - Tastes bitter - Turns red litmus paper blue |
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Electrical Conductivity of Bases |
Bases are electrolytes, so their solutions are good conductors of electricity. - The base separates into its ions as it dissolves in water. NaOH(s) → Na+(aq) + OH-(aq) ("+" and "-" superscript) |
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Colour with Acid-Base Indicators |
- Many chemicals cahnge colour when they are placed in acidic or basic solutions. Indicator: Litmus Colour in acid: Red Colour in base: Blue *For more examples: Page 270* |
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Naming and Chemical Formulas of Bases (contains which polyatomic ions?) |
Many bases are ionic compounds containing hydroxide or carbonate ion. - Naming and chemical formulas are the same as ionic compounds. Example of a Base: Sodium Hydroxide NaOH(aq) Sodium Hydrogen Carbonate NaHCO3(aq) |
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pH and The pH Scale |
pH stands for potential hydrogen. pH: A measure of how acidic or basic a solution is. pH scale: A numerical scale ranging from 0 to 14 that is used to compare to the acidity of solutions. Neutral: Neither acidic or basic; with a pH of 7. |
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Hydrogen and pH |
Acids form hydrogen ions in a solution. The concentration of these hydrogen ions is what determines the solution's pH. The greater the concentration of hydrogen ions in a solution, the stronger the acidic properties. Therefore, highly acidic solutions have a higher hydrogen ion concentration. |
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Hydroxide and pH |
Basic solutions (with a pH greater than 7) have a higher concentration of hydroxide ions than of hydrogen ions. |
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Highly Acidic and Basic Solutions |
They are both very corrosive and reactive, and require very careful handling. |
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pH and Soil |
Different plants grow best in different conditions of soil acidity: for example, benas grow best in soil that is slightly basic.
- So, the pH of soil is altered to improve growing conditions. Example: The addition of compost makes soil more acidic. |
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Acid Leaching |
Soil can be contaminated with toxic chemicals. The process of removing heavy metals from contaminated soils by adding an adic solution to the soil and catching the solutions that drains through. |
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pH and Consumer Products |
Shampoo and Skin Care Products: Designed to have a pH close to neutral. Cleaning products: High concentration of hydroxide ions (basic). |
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pH and Swimming Pools |
The pH of pool water must be maintained with a narrow range of 7.2 to 7.8 (slightly basic). -If too acidic, water irritates the eyes. -If too basic, water becomes cloudy, irritates eyes and chlorine compounds start to lose their effectiveness. Hydrochloric acid (also called "muriatic acid") is often added to reduce pH if it is too high. While, products with sodium carbonate is added to raise pH when it is too low. |
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Neutralization Reactions |
A chemical reaction in which an acid and a base react to form an ionic compound (a salt) and water. The resulting pH is closer to 7. The hydrogen ions in acids and the hydroxide ions in bases react to produce water. *Some bases have carbonate bases; however, we don't need to know the neutralization reaction for that at this level* |
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Neutralization Reaction Equation |
General Format (Double Displacement): AB + CD → AD + CB HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq) acid + base → water + ionic compound |
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Antacids |
Provides relief by neutralizing stomach acids. -The 2 most common active ingredients: Hydroxide & Carbonate compounds Ex: Milk of Magnesia (contains magnesium hydroxide). 2 HCl(aq) + Mg(OH)2 → 2 H2O(l) + MgCl2(aq) |
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Air (What it carries) |
Air carries bacteria, dust particles, moisture, traces of pollutants, and so on. - Some air pollutants contribute to acid precipitation. |
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Acid Precipitation |
Any precipitation (e.g., rain, dew, hail) with a pH less than the normal pH of rain, which is approx. 5.6 - Forms when certain pollutants- most importantly sulfur dioxide and nitrogen oxides- combine with water in the atmosphere. |
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Dry Deposition |
The process in which acid-forming pollutants fall directly to Earth in a dry state. - When they come in contact with water on Earth's surface, acids are formed. |
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Sulfure Dioxide (SO2) |
Sulfur Dioxide SO2
Clear, colourless gas that is produced mainly from burning coal (for electricity) and the mining and refining of metals. The sulfur in the ore reacts with oxygen in the air: S(s) + O2(g) → SO2(g) Sulfur dioxide reacts with more oxygen to produce sulfur trioxide: 2 SO2(g) + O2(g) → 2 SO3(g) Then sulfur trioxide combines with water droplets in the atmosphere to form sulfuric acid: SO3 (g) + H2O(l) → H2SO4(aq) |
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Nitrogen Oxides (NOx)
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Nitrogen Oxides NOx Produced mainly from vehicle emissions (primarily gasoline). Atmospheric nitrogen and oxygen reacts to form nitrogen monoxide: N2(g) + O2(g) → 2 NO(g) *Finish* |
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Environmental Impact of Acid Precipitation (Aquatic Ecosystem, Soils, Forests) |
Aquatic Ecosystem If the pH level continues to decrease, the aquatic life will no longer be able to tolerate. There would be immense loss of fish and organisms higher on the food chain. Soils Metal ions can be dissolved and washed away by acidic water (calcium, magnesium and potassium arre essential nutrients for plant growth). Soils also have a buffering capacity; resisting change in pH levels. However, if the buffering minerals in the soil are used up, the buffering capacity will eventually decrease. Forests The soil will lose valuable nutrients (mentioned above) which will affect the growth and weaken trees. |
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Ecnonmic Impact of Acid Precipitation |
- Loss of wood balued at billions of dollars. - A reduction of fish stocks is affecting Ontario's multibillion dollar recreational fishing industry. - Damages steel structures, limestone buildings, and stone monuments. |
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How to "Clean Up" Acid Precipitation |
- Switch to low-sulfur fossil fuels to generate electricity - The installation of scrubbers to remove sulfure from the emissions of smelting operations and fossil fuel-bruning power plants -Improvements in the pollution control equipment on vehicles -Stricter laws governing vehicle emissions |
