chem 100 exam 2 questions and answers well elaborated

Which is the balanced chemical equation showing hydrogen peroxide (H2O2) decomposing into hydrogen (H2) and oxygen (O2)? - correct answers H2O2→H2+O2 Which is the balanced chemical equation for the reaction of nitrogen (N2) with oxygen (O2) to form NO? - correct answers N2+O2→2NO Which is the correct balanced equation for the complete combustion of ethane in excess oxygen? - correct answers 2C2H6+7O2→4CO2+6H2O Calculate the mass of CO2 produced by the combustion of a tank of gasoline. Assume the mass of gasoline is 46.0 kg and that gasoline is pure octane (C8H18). - correct answers 142 kg The energy that flows from a warmer body to a colder body is called - correct answers heat. The energy stored in the chemical bonds of fossil fuels is a form of ________ energy. - correct answers potential The energy of motion is called ________ energy. - correct answers kinetic The first law of thermodynamics states that - correct answers energy is neither created nor destroyed A chemical reaction accompanied by a release of energy is called a/an ________ reaction. - correct answers exothermic Any chemical or physical change that absorbs energy - correct answers is an endothermic process How is heat energy used to generate electricity in a modern power plant? - correct answers heat boils water to make steam, which drives a turbine Combustion is a chemical process in which a fuel combines with ________ to release energy and form products. - correct answers oxygen Which common process on earth is endothermic? - correct answers The production of oxygen by photosynthesis The heat energy released or absorbed by a chemical reaction is generally determined by the difference between the energy that - correct answers must be put in to break the bonds in the reactants and the energy that is released upon making the bonds in the products. In the petroleum industry, what does a refinery do? - correct answers It separates crude oil into fractions consisting of compounds with similar boiling points Petroleum (crude oil) is a complex mixture of thousands of substances, the majority of which are - correct answers hydrocarbons. The process by which a solution is heated to its boiling point and the vapors are condensed and collected is known as - correct answers distillation Which is produced in the greatest amount from a barrel of petroleum? - correct answers gasoline The general term for plant matter such as trees, grasses, agricultural crops, or other biological material is - correct answers biomass Over the very long run, the energy source that has the greatest potential to meet humanity's needs is - correct answers solar (sun) If a snack cake contains 450 food Calories and Dr. Wattenburger is able to burn 250 Calories by running for one-half an hour, how long must she run to completely burn off the snack cake? - correct answers 54 mins The half-life of carbon-14 is 5,730 years. If you started with 100.0 g of carbon-14, how much would remain after 4 half-lives? - correct answers 6.25g If you have 200.0 g of radioisotope with a half-life of 5 days, how much isotope would remain after 15 days? - correct answers 25.0g Fission is the process of creating energy by - correct answers splitting large nuclei to form smaller, more stable nuclei Which is a common characteristic of both nuclear and conventional electric power plants? - correct answers steam turbines Which feature or process is unique to nuclear power plants when compared to conventional coal- burning power plants? - correct answers control rods Waste created at these power plants must be stored indefinitely. - correct answers nuclear plants What percentage of a radioactive isotope would remain after three half-lives? - correct answers 12.5 percent Which is a known risk associated with nuclear power plants? - correct answers The cooling water source can suffer thermal pollution Sunlight (solar radiation) may be turned directly into electricity using ________ cells. - correct answers photovoltaic Semiconductors are more effective than metals as converters of solar radiation into electricity because - correct answers the energy contained in sunlight gives the valence electrons in the semiconductor atoms the extra energy they need to "flow" throughout the solid. The "doping" of a semiconductor to improve its performance means - correct answers adding small amounts of other elements to the pure semiconductor to change the freedom of electron motion throughout the crystal. Which argument(s) for the increasing use of solar energy is/are valid? I. Solar cells are becoming cheaper and increasingly more efficient II. The cost of generating electricity from fossil fuels is increasing III. Limited and uncertain supply and the increasing requirements for pollution control are raising the cost of using fossil fuels - correct answers I,IIandIII How is wind energy related to the Sun? - correct answers The heat of the Sun drives large-scale movements of air What sort of energy is associated with energy from wind? - correct answers kinetic energy Chemical energy is converted directly into electrical energy in - correct answers a galvanic cell Chemical energy is converted directly into electrical energy in - correct answers a galvanic cell Which is an oxidation half-reaction? - correct answers Zn→Zn2++2e ̄ What condition must be met for a battery to be rechargeable? - correct answers The electrochemical reaction of the battery must be reversible What percentage of Earth's water is in the oceans? - correct answers 97 percent A 4-L sample of water contains 80 μg of lead. What is this lead concentration, in parts per billion (ppb)? - correct answers 20 What is the molarity of sodium chloride in a solution containing 0.50 mol of sodium chloride in 500 mL of water? - correct answers 1.0 M If the lead concentration in water is 1 ppm, then we should be able to recover 1 mg of lead from _____ L of water. - correct answers 1 Predict the products of this reaction: KOH + HNO3 → - correct answers KNO3 + H2O Which reaction represents an acid-base neutralization reaction? - correct answers Be(OH)2 + H2SO4 → BeSO4 + 2H2O Which reaction accounts for the fact that the pH of rain is naturally slightly acidic? - correct answers CO2+H2O→H++HCO3 ̄ Predict the products of the chemical equation: 3 LiOH + H3PO4 → - correct answers Li3PO4+3H2O The attractions between anions and cations throughout a crystal are known collectively as - correct answers ionic bonds Which form of water disinfection continues to provide antibacterial protection after the water leaves the purification plant? - correct answers chlorination What atmospheric component is responsible for the natural acidity of rain? - correct answers carbon dioxide