Test 2 Review Chemical Reactions

Chemical Reactions Unit Test 4.1 Introduction to Chemical Reactions - What is a chemical reaction? o A chemical reaction is when 1+ substances undergo a chemical change to produce 1+ new substances - What are some observations that might indicate that a chemical reaction has taken place? o Observations that may indicate a chemical reaction are: unexpected change in colour, energy is released or absorbed, gas is produced, a precipitate forms. - What is a precipitate? o A precipitate is a solid produced when 2 liquids are combined. - What is a catalyst? o A catalyst is a substance that speeds up the reaction, without being used up in the reaction. - Know the format for writing chemical equations using either chemical names or chemical formulas - Know the state symbols (eg. (s), (l), (g), (aq)) - What is the law of conservation of mass? o The law of conservation of mass states matter cannot be created or destroyed, and thus the total mass of the reactants equals the total mass of products - Know how to balance chemical equations 4.2 Synthesis and Decomposition Reactions - Know the definitions of synthesis and decomposition reactions o Synthesis: A reaction in which two reactants combine to make a large/more complex product Decomposition: A reaction in which a large/more complex compound breaks down to form two (or more) simpler products Know the generic equations of synthesis and decomposition reactions o - - o Synthesis reaction: A + B → AB o Decomposition reaction: AB → A + B See PowerPoint lesson Know the different types of common synthesis and decomposition reactions o Synthesis: ▪ Element + element → compound ▪ Element + compound → compound (if OG element is in compound reactant) ▪ Compound + compound → compound ● Acidic oxide + water → acid ● Basic oxide + water → base ● Acidic oxide + basic oxide → salt o Decomposition ▪ Binary compound → elements ▪ Metal nitrate → metal nitrite + oxygen gas ▪ Metal oxide → metal + oxygen ▪ Metal carbonate → metal oxide + carbon dioxide ▪ Metal hydroxide → metal oxide and water 4.4 Single Displacement Reactions - Know the definition for a single displacement reaction o A reaction in which an element displaces another element in a compound, producing a new compound and a new element - Know the generic equation for a single displacement reaction o A + BC → AC + B - - Know how to use the activity series to predict whether or not a single displacement reaction will occur (for metals, acids, water, and halogens), and how quickly the reaction will occur o Activity Series: An element HIGHER (more reactive) on the list can displace elements below it from compounds, but not ones above it. o The farther apart the two elements are, the more likely that the reaction will occur quickly Know the different types of common single displacement reactions studied (all use activity series): o Metal + compound → metal + compound o Halogen + compound → halogen + compound o Metal + water → hydrogen gas + base (metal + OH) o Metal + acid (hydrogen + nonmetal) → hydrogen gas + ionic compound ▪ i.e. 2Na(s) + 2H2O(l) → H2(g) + 2NaOH ▪ i.e. Li(s) + H2SO4(aq) → H2(g) + Li2SO4(aq) 4.6 Double Displacement Reactions - Know the definition of a double displacement reaction o A reaction in which elements in two compounds displace each other and produce two new compounds - Know the generic equation of a double displacement reaction o - AB + CD → AD + BC Know how to use the solubility table to predict the solubility of an ionic compound Know the different types of common double displacement reactions studied: o Precipitate Forms - Compound + compound (check solubility table, if both products are soluble, no precipitate) o Gas Forms - Occurs with sulfide, carbonate, or sulfite with an acid Types of gas produced - Sulfide → hydrogen sulfide - Carbonate → carbon dioxide (through decomposition of carbonic acid into water as well) - Sulfite → sulfur dioxide (through decomposition of sulfurous acid into water as well) o Neutralization - Acid + base → water + ionic compound - Base can be a hydroxide or carbonate - If with a carbonate, compound decomposes and additional product of CO2 5.1 The Combustion of Hydrocarbons - What is combustion? What are organic compounds? What are hydrocarbons? o Combustion: A chemical reaction in which a fuel burns in oxygen o o - - Organic compound: A molecular compound containing 1+ carbon-hydrogen bonds; usually what most fuels are composed of. Hydrocarbon: An organic compound consisting entirely of hydrogen and carbon What is complete combustion? o The combustion/burning of a hydrocarbon in plentiful supply of oxygen to produce carbon dioxide, water, and energy. Controlled/ideal conditions What is the general chemical equation for the complete combustion of a hydrocarbon? o CxHy + O2(g) → CO2(g) + H2O(g) + energy - Why is complete combustion often desirable over incomplete combustion? o Produces cleanest and hottest flames, releases more energy - What is incomplete combustion? o The combustion/burning of a hydrocarbon in limited supply of oxygen, with various products. o - Occurs when hydrocarbon is in enclosed space. Uncontrolled/less than ideal conditions o “Fuel-rich”: lots of fuel require, limited oxygen What are some of the possible products of the incomplete combustion of a hydrocarbon? o Carbon (soot), carbon monoxide, carbon dioxide, water, energy Why is incomplete combustion often less desirable over complete combustion? Name one instance when incomplete combustion is more desirable than complete combustion. o Only portion of energy released by reaction may be obtained. o Soot particles are inhalation hazard causing respiratory problems - toxic, not filterable o Carbon monoxide poisoning o USEFUL: Cold lawn mower is easier to start if a fuel-rich mixture enters the engine 5.3 Elements and Their Oxides - What is an oxide, acid, base, acidic oxide, and basic oxide? o Oxide: A compound composed of oxygen and another element o o Acid: A compound that produces hydrogen ions when mixed with water Base: A compound that produces hydroxide ions when mixed with water Acidic Oxide: An oxide that forms an acidic solution when dissolved in water; molecular compounds that are often gases at room temperature; NON-METALLIC OXIDE o Basic Oxide: An oxide that forms a basic solution when dissolved in water; ionic compounds that are often solids at room temperature; METALLIC OXIDE What is the pH scale? Do acids and bases have low pH values or high pH values? o pH scale indicates the concentration of hydrogen ions present in a solution o - o - - Acids - low pH, base - high pH hello child i come from the wild west yeeeeHWAA List 3 elements that can form acidic oxides. Know the chemical equations for the formation of these oxides. o Sulfur oxides: S(s) + O2(g) → SO2(g) and 2SO2(g) + O2(g) → 2SO3(g) o Nitrogen oxides: N2(g) + O2(g) → 2NO(g) and o Carbon oxides: C(s) + O2(g) → CO2(g) and 2NO(g) + O2(g) → 2NO2(g) 2C(s) + O2(g) → 2CO(g) What is a catalytic converter and how does it work? o It prevents most of nitrogen oxides and other pollutants from being discharged in the exhaust of a car, since it is can form toxic respiratory irritants after leaving the exhaust of a car. - ▪ The interior is coated with beads of platinum, palladium or rhodium catalyst, which when in contact decomposes the nitrogen oxides to nitrogen and oxygen (harmless) Know one example of a basic oxide and the chemical formula for its formation. What are some uses of basic oxides? o 4Na(s) + O2(g) → 2Na2O (s) + energy - See PowerPoint lesson o Uses of basic oxides: detergent, paper, glass, cement, paper 5.4 Neutralization Reactions - What are neutralization reactions? o When an acid reacts with a base to produce a solution with a pH closer to 7. Products are water and ionic compound (usually salt): o Acid + base → water + ionic compound - What are two different ways to neutralize an acidic solution o With a hydroxide compound (OH) o - With a carbonate compound (CO3) Understand how the neutralization of an acidic solution with a carbonate compound is a 2 step reaction o After the double displacement, the carbonic acid immediately decomposes to water and carbon dioxide Nuclear Reactions - What is a nuclear reaction? o Reactions in which the changes involved are within the nucleus of an atom - Know the terms radioactive decay, nuclear radiation, radioisotope and radioactive o Radioactive decay: The spontaneous disintegration of unstable isotopes o Nuclear radiation: Energy or very small particles emitted from the nucleus of a radioisotope as it decays o o - Radioisotope: An isotope that spontaneously decays to produce two or more smaller nuclei and radiation Radioactive: Having the potential to emit nuclear radiation upon decay Know α-decay, β-decay, and γ-radiation, and the associate particles/energies: Alpha can’t penetrate paper Beta can penetrate paper, NOT aluminum Gamma can penetrate paper and aluminum, NOT lead - Be able to recognize α-decay, β-decay, and γ-radiation in nuclear equations Be able to write/balance nuclear equations (top: mass #, bottom: atomic #/protons) Transmutation, fission, fusion o Transmutation: When a nucleus is struck/bombarded by a proton, neutron or another nucleus (i.e. an alpha particle) and changes the nucleus’ identity o Fission: When a massive nucleus splits into two or more lighter nuclei. Can occur spontaneously OR WITH A NEUTRON o Fusion: When small nuclei combine to form a larger nucleus, accompanied by the release of a tremendous amount of energy. ** YOU MUST KNOW HOW TO WRITE AND BALANCE CHEMICAL EQUATIONS** ** BE SURE TO REVIEW THE CHEMICAL EQUATIONS SCRAMBLE ACTIVITY **