Unit 3 - Rules and Other Facts

• Synthesis is when the reactant can be any combo of elements or compounds, but they always create a single compound.
• Synthesis reactions are usually exothermic (release energy) and can occur naturally or by an initial application of energy
• Synthesis Rules:

  Metal + oxygen = metal oxide

  Nonmetal + oxygen = nonmetallic oxide

  Metal Oxide + Water = Metallic Hydroxide

  Nonmetallic oxide + water = acid

  metal + nonmetal = salt
• Decomposition is when one reactant is broken down into one or more products. They are typically endothermic (requires/absorbs energy) and may require heat (heat, flame, uv light) to occur. Others may occur at room temperature.
• Decomposition Products

  Metallic carbonates = Metallic Oxide + Carbon dioxide

  Metallic Hydroxides = Metallic Oxide + Water

  Metallic Chlorates = Metallic chloride + oxygen

  Acids = Nonmetallic oxide + water

  Nonmetallic Hydroxide = Nonmetallic oxide + water
• Metals easily lose electron because of low ionization energy (alkali metals). Alkaline earth metals follow the same trend and together they make up the top six most reactive metals on the activity series
• The Activity series is a ranking of the reactivity of metals in aqueous reactions. Some metals lose electrons more easily than others, so their readiness to be oxidized means they are powerful reducing agents.
• A single displacement reaction is when an element is reacted with a compound and it trades places with one part of the compound.
• Double Displacement reactions are when two compounds react together and the first part of each compound trades places with one another.
• The solubility table is sued to determine the states of compounds.

  If the cation and the anion match in the top row, the ions have high solubility and are aqueous. If the cation and anion match in the bottom row, the ions have low solubility and form a solid.
• There are three unique cases for double displacements:

  An ammonium compound + a hydroxide compound form ammonia and water.

  An acid and a carbonate compound form carbon dioxide and water

  Neutralizations create salt and water.
• A hydrocarbon is a compound composed only of carbon and hydrogen elements.
• Many hydrocarbons are used as fuel because their combustion release large amounts of heat energy. The carbon-carbon and carbon-hydrogen bonds have a lot of energy stored in them. When a hydrocarbon burns the products of the reaction depend on the amount of oxygen available
• Complete combustion occurs when there is an excess amount of oxygen available. Energy is released from the reaction in the form of heat and light.
• Complete combustion is more efficient at producing heat/energy than light and can be identified from the blue flame that it produces. Complete combustion always produces water and carbon dioxide
• In incomplete combustions, the products are more hazardous carbon monoxide and carbon soot can be produced. Other products are water vapour and carbon dioxide.
• Incomplete combustion reactions are efficient at producing light and a bright yellow flame, but they are less efficient at producing heat than complete combustion
• Carbon monoxide is an odourless and colourless toxic gas. The gas can bind to oxygen in the blood to decrease the number of available oxygen binding sites in the body, leading to suffocation.
• Incomplete combustion reacts with a limited amount of oxygen and its products will be many different ratios of carbons products, but there will always be Carbon or carbon monoxide or both. There is always carbon dioxide and water vapour produced
• Concentration is the relevant amount of a given substance contained within a particular volume of space.
• Molarity is the measure of concentration that involves the number of moles of solute per volume of solvant
• pH is the measure of an acide of base's strength
• Based off Arrhenius Theory:

  • An acid is a substance that ionizes in water to form one or more hydrogen ions
  • A base is a substance that dissociates in water to form one or more hydroxide ions
• Acids have a pH less than 7. They produce hydrogen atoms in a solution, dangerous when concentrated, produce H2 gas when reacted with metals, turns blue litmus paper red, neutralizes an equivalent amount of base and are a proton donor.
• Strong Acids include: H2SO4 (sulfuric Acid), HCl (HydroChloric Acid), H3PO4 (phosphoric acid) and HNO3 (Nitric Acid)
• Weak acids include: HC2H3O2 (acetic acid), H2CO3 (Carbonic acid), HC6H7O7 (Citric acid) and HC9H7O4 (aspirin).
• The difference between strong and weak acids is ionizability. Strong acids ionize complete in water (>99%) and weak acids ionize only slightly in water (<50%)
• Bases have a pH greater than 7, produce hydroxide ions in solutions, dangerous when concentrated, proton (H+) acceptor, slippery when wet, turns red litmus paper blue, neutralizes an equal amount of acid.
• Examples of strong bases: NaOH (Sodium hydroxide), Potassium hydroxide (KOH) and NaClO (sodium hypochlorite)
• Weak bases include: NH4OH (ammonium hydroxide), NH3 (ammonia), soap and tapwater
• Neutral substances have a pH equal to 7, often form salts from neutralization reactions, are neither acids nor bases
• Examples of neutral substances is pure distilled water and NaCl (table salt)
• The p in pH stands for potentz and the h in pH stands for hydrogen
• In a neutral solution the concentration = 1.0 x 10^-7 mol/L

  In an acidic solution the concentration > 1.0 x 10^-7 mol/L

  In a basic solution the concentration < 1.0 x 10^-7 mol/L
• When we neutralize something we bring it closer to 7 on the pH scale. The easiest things to neutralize are near the middle of the pH scale. Its hard and dangerous to neutralize a strong acide with a strong base, since it causes a violent reaction with the release of concentrated poisonous gas
• A neutralization will always produce water, a salt and energy
• There are two types of indicators

  • Indicators that only tell if a solution is an acid or a base (ex. litmus paper)
  • Indicators that show the strength of an acid or base
  • Indicators are in solid or liquid form
• Titrations are a method used to find the concentration of a solution
• The concentration of an unknown base is difficult to determine due to two factors

  • Many bases are hygroscopic; they absorb water which will dilute and change their concentration
  • Dissolved CO2 and atmospheric CO2 will neutralize a small amount of the base, thus changing the concentration