CHEMISTRY CUMULATIVE FINAL EXAM AND STUDY GUIDE | ALL EXAM QUESTIONS AND CORRECT ANSWERS | Exams Chemistry | Docsity (2024)

Download CHEMISTRY CUMULATIVE FINAL EXAM AND STUDY GUIDE | ALL EXAM QUESTIONS AND CORRECT ANSWERS and more Exams Chemistry in PDF only on Docsity! CHEMISTRY CUMULATIVE FINAL EXAM AND STUDY GUIDE | ALL EXAM QUESTIONS AND CORRECT ANSWERS | ALREADY GRADED A+ | LATEST VERSIONS 2024 CHEMISTRY CUMULATIVE FINAL EXAM What is the molecular geometry of the bonds around the carbon in CCl4? A) tetrahedral B) Bent C) Linear D) Pyramidal E) Trigonal planar ------CORRECT ANSWER---------------A) tetrahedral What is the geometry of CS2? A) linear B) bent C) trigonal planar D) trigonal pyramidal ------CORRECT ANSWER---------------A) linear The strongest noncovalent interaction (Intermolecular forces) that can occur between hydrocarbons is _____. A) dipole-dipole forces B) hydrogen bonding C) ion-dipole interaction D) London force (Dispersion force) ------CORRECT ANSWER---------------D) London force (Dispersion force) A gas cylinder at a pressure of 4408 torr contains a mixture of N2, O2, and helium gases. If the partial pressure of N2 gas is 1520 torr and the partial pressure of helium is 25 torr, what is the partial pressure of O2? A) 760 torr B) 4020 torr C) 5953 torr D) 2863 torr ------CORRECT ANSWER---------------D) 2863 torr A cylinder of gas originally at 28.0°C and 1.00 atm of pressure is heated to 112.0°C. What is the new pressure? A) 4.00 atm B) 0.250 atm C) 0.782 atm D) 1.28 atm ------CORRECT ANSWER---------------D) 1.28 atm What is the %(w/v) of a 1500mL solution containing 45 g of NaCl? A) 5% B) 3% C) 2% D) 0.030% ------CORRECT ANSWER---------------B) 3% If 25.0 mL of 3.0 M HCl are diluted to give a final volume of 150 mL, what is the new concentration? A) 0.50 M B) 75 M C) 2.0 M D) 4.5 M ------CORRECT ANSWER---------------A) 0.50 M Which of the following compounds has the lowest boiling point? A) heptane B) 3-methylpentane C) 2-methylpentane D) hexane E) 2,2-dimethylbutane ------CORRECT ANSWER---------------E) 2,2- dimethylbutane According to their definitions, which of the following would not occur as unsaturated hydrocarbons? A) alkane B) alkene C) alkyne D) none of the above are correct ------CORRECT ANSWER---------------A) alkane Organic compounds responsible for flavors in fruits and the scent of flowers are A) Alkanes B) Alcohols C) Ethers D) Esters E) Ketones ------CORRECT ANSWER---------------D) Esters The number 390000, expressed correctly in scientific notation, is A) 3.9 x 10-6 B) 3.9 x 105 C) 3.9 D) 3.9 x 10-5 ------CORRECT ANSWER---------------B) 3.9 x 105 Solids have _____ shape and _____ volume. A) fixed/variable B) fixed/fixed C) variable/fixed D) variable/variable ------CORRECT ANSWER---------------B) fixed/fixed Which is a unit of measure of mass? A) liter B) ºC C) kilogram D) Joule ------CORRECT ANSWER---------------C) kilogram All atoms of the same element that have the same atomic number, but different mass numbers are known as _____ A) protons B) moles C) isotopes D) isomers ------CORRECT ANSWER---------------C) isotopes Choose the incorrect statement about the proton: A) The proton has the atomic mass of 1 amu B) The proton has the same charge as the neutron. C) The proton has greater mass than an electron D) The proton and the neutron have approximately the same atomic mass - -----CORRECT ANSWER---------------B) The proton has the same charge as the neutron. The normal dosage for azinthromycin, an antibiotic, is 3.3 mg/kg. What is the proper dose for a 150 lb patient? (Given: 1kg = 2.205 lbs) A) 100 mg B) 224 mg C) 300 mg D) 495 mg ------CORRECT ANSWER---------------B) 224 mg At 20 oC, chloroform (CHCl3) has a density of 1.489 g/mL. What is the mass of 7.52 mL of chloroform at 20 oC? A) 0.198 g B) 13.4 g C) 5.05 g D) 11.2 g ------CORRECT ANSWER---------------D) 11.2 g What makes carbon such a unique element? A) Elemental carbon comes in two forms, diamond and graphite. B) Carbon forms four bonds, although the ground state configuration would predict the formation of fewer bonds. C) Carbon forms covalent bonds rather than ionic bonds. D) To a greater extent than any other element, carbon can bond to itself to form straight chains, branched chains and rings. E) Carbon has two stable isotopes, carbon-12 and carbon-13 ------ CORRECT ANSWER---------------D) To a greater extent than any other element, carbon can bond to itself to form straight chains, branched chains and rings. A molecule with the formula C3H8 is a(n): A) hexane B) propane C) decane D) butane E) ethane ------CORRECT ANSWER---------------B) propane The general formula for noncyclic alkenes is: A) CnH2n+2 B) CnH2n A radioisotope has a half-life of 4 days. How much of a 20-gram sample of this radioisotope remains at the end of 16 day time period? A) 10 gram B) 5 gram C) 2.5 gram D) 1.25 gram ------CORRECT ANSWER---------------D) 1.25 gram The formula for ammonium chloride is A) NH4Cl4 B) NH4Cl C) NCl D) AmCl ------CORRECT ANSWER---------------B) NH4Cl The number of covalent bonds that a nitrogen atom is expected to form is A) 1 B) 2 C) 3 D) 4 ------CORRECT ANSWER---------------C) 3 According to the octet rule, aluminum (Al) will form which of the following monoatomic ions? A) Al- B) Al2+ C) Al3+ D) Al3- ------CORRECT ANSWER---------------C) Al3+ Which statement is NOT true about subatomic particles? A) Protons and electrons are found in the nucleus. B) Neutrons have no electrical charge. C) Electrons contain much less mass than neutrons. D) Electrons are found in orbitals around the nucleus. ------CORRECT ANSWER---------------A) Protons and electrons are found in the nucleus. How many valence electron potassium will have A) 19 B) 9 C) 1 D) 2 ------CORRECT ANSWER---------------C) 1 Which of the following is an anion? A) I- B) Al3+ C) Mg D) F ------CORRECT ANSWER---------------A) I- CO3 2- is the _______ion A) carbonate B) hydrogencarbonate (bicarbonate) C) acetate D) cyanide ------CORRECT ANSWER---------------A) carbonate How many protons and electrons does Mg2+ have? A) 12 protons and 12 electrons B) 12 protons and 14 electrons C) 14 protons and 12 electrons D) 12 protons and 10 electrons ------CORRECT ANSWER---------------D) 12 protons and 10 electrons How many valence electrons must O atom gain to reach an octet? A) 0 B) 1 C) 2 D) 3 ------CORRECT ANSWER---------------C) 2 The formula for ammonium chloride is A) NH4Cl4 B) NH4Cl C) NCl D) AmCl What is the molar mass of isopentyl acetate, C7H14O2, a compound responsible for the odor of bananas? A) 130.19 g B) 98.32 g C) 146.58 g D) 119.35 g E) 13.19 g ------CORRECT ANSWER---------------A) 130.19 g According to the octet rule, aluminum (Al) will form which of the following monoatomic ions? A) Al- B) Al2+ C) Al3+ D) Al3- ------CORRECT ANSWER---------------C) Al3+ What is the geometry of CS2? A) linear B) bent C) trigonal planar D) trigonal pyrimidal ------CORRECT ANSWER---------------A) linear A) thymine B) uracil C) cytosine D) guanine ------CORRECT ANSWER---------------A) thymine The bonding forces between two DNA strands in a double helix are A) peptide linkages B) phosphate bonds C) acetal bonds D) hydrogen bonds ------CORRECT ANSWER---------------D) hydrogen bonds -phosphate-sugar-phosphate-sugar- is an example of a ____ backbone. A) human B) chemical C) nucleic acid D) all the choices ------CORRECT ANSWER---------------C) nucleic acid The sequence of one strand of DNA is 5' TCGATC 3'. The sequence of the complementary strand would be A) 5' AGCTAG 3' B) 5' TCGATC 3' C) 5' CTAGCT 3' D) 5' GCTAGC 3' E) 5' GATCGA 3 ------CORRECT ANSWER---------------A) 5' AGCTAG 3' What is produced at the end of glycolysis? A) Pyruvic acid B) Archadonic acid C) Acetyl coA D) Fatty acid ------CORRECT ANSWER---------------A) Pyruvic acid What is present in a nucleotide that is not found in a nucleoside? A) a phosphate B) a monosaccharide C) an alcohol group D) a nitrogen base ------CORRECT ANSWER---------------A) a phosphate The process by which DNA makes RNA molecules is known as _____. A) replication B) transcription C) translation D) reverse transcription ------CORRECT ANSWER---------------B) transcription which of the following is not an step in glucose metabolism A) Glycolysis B) citric acid cycle C) nitrogen cycle D) electron transport chain E) formation of acetyl coA ------CORRECT ANSWER---------------C) nitrogen cycle Synthesis of proteins from aminoacids is an example of A) catabolism B) anabolism C) parabolism D) metabolism ------CORRECT ANSWER---------------A) catabolism A kitten's normal body temperature is 102 ºF. Express this temperature in ºC A) 5.7 ºC B) 38.9 ºC C) 56.7 ºC D) 184 ºC ------CORRECT ANSWER---------------B) 38.9 ºC What do you do to test a hypothesis? A) Guess B) Publish a Scientific Paper C) Disorganized D) Design an Experiment ------CORRECT ANSWER---------------D) Design an Experiment A strong acid: A) does not dissolve in water B) ionizes slightly in water to give molecules and a few ions C) ionizes 100% in water to give all ions D) dissolves in water only as molecules ------CORRECT ANSWER------------ ---C) ionizes 100% in water to give all ions In the equation: HF + H2O ----> H3O+ + F- A) H2O is a base and HF is its conjugate acid. B) H2O is an acid and HF is the conjugate base. C) HF is an acid and F- is its conjugate base. D) HF is a base and H3O+ is its conjugate acid. E) HF is a base and F- is its conjugate acid. ------CORRECT ANSWER------ ---------C) HF is an acid and F- is its conjugate base. Which is the conjugate acid of NH3? A) NH2- B) NH4+ C) HNO3 D) baking cookies ------CORRECT ANSWER---------------A) melting of ice Which set of coefficients balances the following equation: _____C5H12 + ________O2 --> ________CO2 + ______H2O A) 1,1,5,6 B) 1,5,5,6 C) 1,5,5,1 D) 1,8,5,6 ------CORRECT ANSWER---------------D) 1,8,5,6 A 40 mg dose of iodine-131 with a half-life of 8 days is administered to a patient. How long will it take for the iodine to decay so that there are only 5 mg remaining? A) 8 days B) 16 days C) 32 days D) 24 days ------CORRECT ANSWER---------------D) 24 days A sample of nitrogen gas exerts a pressure of 9.80 atm at 32 degrees C. What would its temperature be (in degrees C) when its pressure is increased to 11.2 atm? A) 75.6 degrees C B) - 6.14 degrees C C) 48.7 degrees C D) 349 degrees C ------CORRECT ANSWER---------------A) 75.6 degrees C Polocaine® is a local anesthetic administered by injection. A 50-mL, multidose vial is available containing 100 mg of mepivacaine hydrochloride. What is the %w/v concentration of the solution? A) 0% B) 0.2% C) 50% D) 5,000% ------CORRECT ANSWER---------------B) 0.2% Which of the following is located in the nucleus of an atom? A) Protons B) Neutrons C) Electrons D) Protons and neutrons ------CORRECT ANSWER---------------D) Protons and neutrons The geometry of the H2S molecule is best described as A) Trigonal planar B) Tetrahedral C) Bent D) Linera E) Trigonal pyramidal ------CORRECT ANSWER---------------C) Bent Which compound is a unsaturated hydrocarbon? A) ethane B) ethyl chloride C) ethyne D) ethanol ------CORRECT ANSWER---------------C) ethyne Which compound has the lowest boiling point? A) CH3CHO B) CH3CH3 C) CH3 CH2OH D) CH3CO CH2CH3 ------CORRECT ANSWER---------------B) CH3CH3 A solution has a [H3O+] of 1 x 10-5. What is the [OH-] of the solution? A) 1 x 10-5 B) 1 x 10-7 C) 1 x 10-9 D) 1 x 10-14 ------CORRECT ANSWER---------------C) 1 x 10-9 A person who suffers from hyperventilation will exhibit signs of A) respiratory acidosis. B) respiratory alkalosis. C) metabolic acidosis. D) metabolic alkalosis. ------CORRECT ANSWER---------------B) respiratory alkalosis. Which of the following molecules is smallest? A) sucrose B) glucose C) cellulose D) starch ------CORRECT ANSWER---------------B) glucose All of the following are storage carbohydrates except A) starch B) glycogen C) amylopectin D) amylose E) cellulose ------CORRECT ANSWER---------------E) cellulose Which two monosaccharides combine to form sucrose? A) α-glucose and α-fructose B) α-fructose and α-ribose C) α-glucose and β-glucose D) α-galactose and α-fructose ------CORRECT ANSWER---------------A) α- glucose and α-fructose Which diagram best illustrates the atomic model that Rutherford derived from his gold foil experiment? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------A To explain the photoelectric effect, Albert Einstein linked the photoelectric effect to an idea from which scientist? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------C) Max Planck A student writes the following statements about the relationship between mass defect and nuclear binding energy. 1. When an isotope's protons and neutrons come together to form a nuclide, a small amount of mass is converted to energy. 2. An equivalent amount of energy must be added to the nuclide to split apart its protons and neutrons. 3. Statement 1 describes the isotope's nuclear binding energy, and statement 2 describes the isotope's mass defect. Which statement is correct? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------C) 1 and 2 only In which isotope is the strong nuclear force not strong enough to balance electrostatic forces between protons? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------D) uranium-238 Which is a correct comparison between the modern quantum model and John Dalton's model of the atom? ------CORRECT ANSWER---------------C) The modern model recognizes particles in the atom, whereas Dalton's model does not. What did J. J. Thomson observe when he applied electric voltage to a cathode ray tube in his famous experiment? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------B) The glass opposite of the negative electrode started to glow. The mass number of a chromium atom is 52 and it has 24 protons. How many neutrons does this atom have? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------B) 28 Which of these properties is the best one to use for identification of an element? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------B) the number of protons in the atomic nucleus Which scientist's law about the ratios of masses of elements in a compound did John Dalton's work on the atomic structure help to explain? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------D) Joseph Proust Which is a component of John Dalton's atomic theory? (Atoms and the Atomic Theory) ------CORRECT ANSWER---------------C) An atom is a small particle that cannot be broken down. (Elements and the Periodic Table) Which property would xenon most likely have? ------CORRECT ANSWER---------------A) It is stable (Elements and the Periodic Table) Which statement describes heterogeneous mixtures? ------CORRECT ANSWER---------- -----A) They are made up of two or more pure substances that are not chemically bonded together. (Elements and the Periodic Table) An atom of an element is shown by the model. mc016-1.jpg How is this model useful? ------CORRECT ANSWER---------------A) It shows how electrons are distributed in the shells of an iron atom. (Elements and the Periodic Table) Which element has an ion that is smaller than an ion of calcium? ------CORRECT ANSWER---------------D) Magnesium (Elements and the Periodic Table) Which shows the electron configuration for zinc (Zn)? ------CORRECT ANSWER---------- -----D) [Ar]4s23d10 (Elements and the Periodic Table) What is the electron configuration for helium (He)? ------CORRECT ANSWER-------------- -B) 1s^2 (Elements and the Periodic Table) Chuck wants to know how many electrons in an atom are not paired up. Which model would be best for Chuck to write out? ------CORRECT ANSWER---------------D) an orbital notation of the atom (Elements and the Periodic Table) Which is most likely true about electronegativity? ------CORRECT ANSWER--------------- C) It tends to increase across a period. (Elements and the Periodic Table) Which is a set of valid quantum numbers? ------CORRECT ANSWER---------------D) n = 4, l = 3, m = 3 (Elements and the Periodic Table) Which best describes the trends in electronegativity on the periodic table? ------ CORRECT ANSWER---------------A) Electronegativity increases up and to the right. (States and Changes of Matter) Which commercial technology commonly uses plasmas? ------CORRECT ANSWER------ ---------C) a television (States and Changes of Matter) Why do amorphous solids not have a long-range order in the arrangement of their particles? ------CORRECT ANSWER---------------A) Their formation involves very rapid cooling. (States and Changes of Matter) A gaseous substance turns into a solid. Which best describes this change? ------ CORRECT ANSWER---------------B) A substance that has no specific volume changes to a substance that has a specific volume. (States and Changes of Matter) The diagrams show gases that are stored in two separate but similar containers. mc014-1.jpg If both gases are at the same temperature, which one has the greater pressure? ------ CORRECT ANSWER---------------C) gas 2 because it has more particles that are colliding (States and Changes of Matter) Consider the temperature versus time graph below. mc019-1.jpg At what temperature is the substance a heated gas? ------CORRECT ANSWER----------- ----C) above 100°C (States and Changes of Matter) Which sequence represents the relationship between pressure and volume of an ideal gas as explained by the kinetic-molecular theory? ------CORRECT ANSWER--------------- C) smaller volume mc008-6.jpg crowded particles mc008-7.jpg more collisions mc008- 8.jpg higher pressure (States and Changes of Matter) Which is an aspect of the kinetic-molecular theory and can be used to explain the compressibility of plasmas? ------CORRECT ANSWER---------------A) Particles move independently of one another and are widely spaced. (States and Changes of Matter) Which statement describes a limitation of the kinetic-molecular theory for a gas? ------ CORRECT ANSWER---------------A) Which statement describes a limitation of the kinetic-molecular theory for a gas? (Chemical Bonding: Part 1) Which describes a step in the process of forming an ionic bond? ------CORRECT ANSWER---------------A) A metal atom loses electrons and becomes a positive ion. (Chemical Bonding: Part 1) What is a three-dimensional structure that represents the alternating pattern of particles in a crystal? ------CORRECT ANSWER---------------B) a crystal lattice (Chemical Bonding: Part 1) Which is a property of covalent compounds? ------CORRECT ANSWER---------------C) They have a low boiling point. (Chemical Bonding: Part 1) Based on its location in the periodic table, what can most likely be predicted about sulfur? ------CORRECT ANSWER---------------C) It has six valence electrons available for bonding. (Chemical Bonding: Part 1) Which compound most likely contains polar covalent bonds? ------CORRECT ANSWER- --------------D) NF3 (Chemical Bonding: Part 1) Which of the following do Lewis structures help us understand? ------CORRECT ANSWER---------------B) the number of electrons that are involved in the bonding of the molecule (Chemical Bonding: Part 1) Which chemical species can form an ionic bond with an anion? ------CORRECT ANSWER---------------A) Hg22+ (Chemical Bonding: Part 1) Which best describes why NH4+ can form an ionic bond with Cl-? ------CORRECT ANSWER---------------B) Its positive charge is attracted to the negative charge of Cl-. (Chemical Bonding: Part 1) A substance conducts an electric current when it is in the liquid state. What would the conductivity of the substance in solid form indicate about the type of bond in the substance? ------CORRECT ANSWER---------------C) If the solid is conductive, the bonds are metallic. (Chemical Bonding: Part 1) Which statement describes the valence electrons in metallic bonds? ------CORRECT ANSWER---------------C) They are shared among many atoms (Chemical Bonding: Part 1) Which type of bonding involves the complete transfer of a valence electron from a less electronegative atom to a more electronegative one? ------CORRECT ANSWER----------- ----A) ionic bonding (Chemical Bonding: Part 1) Which element has the lowest ionization energy? ------CORRECT ANSWER--------------- C) cesium (Changes in Matter and Chemical Reactions) Which of these is an example of a physical change? ------CORRECT ANSWER------------ ---B) solid ice, when heated, turning into liquid water (Changes in Matter and Chemical Reactions) Iron reacts with oxygen to form iron oxide (rust). Which best describes this statement? -- ----CORRECT ANSWER---------------C) Iron oxide is formed by rearranging atoms. (Changes in Matter and Chemical Reactions) Which word equation shows lithium oxide being formed from the reaction between oxygen and lithium? ------CORRECT ANSWER---------------B)lithium + oxygen mc027- 2.jpg lithium oxide (Changes in Matter and Chemical Reactions) Shown below is a chemical reaction. Fe + CuCl2 mc009-1.jpg FeCl2 + Cu Which pair of substances are the products? ------CORRECT ANSWER---------------D) FeCl2 and Cu (Changes in Matter and Chemical Reactions) An unbalanced chemical equation for the reaction of boron fluoride with lithium sulfite is shown below. BF3 + Li2SO3 mc023-1.jpg B2(SO3)3 + LiF What is the coefficient of lithium fluoride in the balanced chemical reaction? ------ CORRECT ANSWER---------------D) 6 (Changes in Matter and Chemical Reactions) Which statement describes a chemical property of water? ------CORRECT ANSWER----- ----------A) It reacts with sodium metal. (Changes in Matter and Chemical Reactions) Sodium combines with water to produce sodium hydroxide and hydrogen gas. Which word equation represents this violent reaction? ------CORRECT ANSWER---------------B) sodium + water mc002-2.jpg sodium hydroxide + hydrogen (Changes in Matter and Chemical Reactions) Which statement describes an extensive property of matter? ------CORRECT ANSWER- --------------C) It changes with the amount of sample that is present. (Changes in Matter and Chemical Reactions) Which process is a chemical change? ------CORRECT ANSWER---------------D) loss of atmospheric ozone (Changes in Matter and Chemical Reactions) During an experiment, Jon exhales through a straw and blows bubbles into a solution. Which observation would most likely indicate that a chemical reaction is occurring? ------ CORRECT ANSWER---------------D) The solution becomes cloudy with a white solid. (Changes in Matter and Chemical Reactions) This formula equation is unbalanced. BaCl2(aq) + Na2CO3(aq) mc017-1.jpg BaCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation? ------ CORRECT ANSWER---------------B) 2 (Changes in Matter and Chemical Reactions) When a strip of magnesium metal is touched to a flame, a bright light and a whitish substance are produced. Why is the burning of magnesium considered a chemical change? ------CORRECT ANSWER---------------C) because a new substance is formed (Changes in Matter and Chemical Reactions) A chemical reaction that has the general formula of AB → A + B is best classified as a BLANK reaction. ------CORRECT ANSWER---------------decomposition (Changes in Matter and Chemical Reactions) Which type of reaction is Mg + S → MgS? ------CORRECT ANSWER---------------B) synthesis (Changes in Matter and Chemical Reactions) What is produced during the replacement reaction of Cu(NO3)2 and Zn? ------ CORRECT ANSWER---------------D) Zn(NO3)2 + Cu (Stoichiometry) In a chemical reaction, substance R reacts with compound XY to produce 47.0 g of compound RX. If the theoretical yield of RX is 56.0 g, what is its percent yield? Use mc018-1.jpg. ------CORRECT ANSWER---------------C) 83.9% (Stoichiometry) The pictures below show samples of different substances. mc015-1.jpg The mass and volume of each sample differ from the mass and volume of the other samples. Is it possible for each sample to contain 1 mol of each substance? ------ CORRECT ANSWER---------------C) Yes, because the number of moles is not dependent on the mass or the volume. (Stoichiometry) A teacher describes a mathematical system that can be used to convert the weight of water to the mass of water. What is the teacher most likely describing? ------CORRECT ANSWER---------------D) dimensional analysis (Stoichiometry) Juana performs the calculation below. 2Al2O3 mc019-1.jpg 4Al + 3O2 How many moles of oxygen are produced if 11.0 mol of Al are produced? ------ CORRECT ANSWER---------------A) 8.25 mol (Reaction Rates and Chemical Equilibrium) Consider the reaction pathway graph below. mc012-1.jpg Which kind of reaction does this graph represent? ------CORRECT ANSWER--------------- B) endothermic because mc012-3.jpgHrxn = 876.8 kJ (Reaction Rates and Chemical Equilibrium) In the hypothetical reaction below, substance A is consumed at a rate of 2.0 mol/L·s. If this reaction is at dynamic equilibrium, at what rate will substance B be consumed? A mc005-1.jpg B ------CORRECT ANSWER---------------C) 2.0 mol/L·s (Reaction Rates and Chemical Equilibrium) According to Le Chatelier's principle, what happens when the concentration of a product is reduced in a chemical reaction that was in equilibrium? ------CORRECT ANSWER----- ----------A) The equilibrium shifts to the right to favor the formation of products. (Reaction Rates and Chemical Equilibrium) What is the main reason that it takes 2 to 3 minutes for the reaction to occur between sucrose and sulfuric acid in the dehydration of sucrose? ------CORRECT ANSWER------- --------A) The activation energy needs to be overcome in the reaction. (Reaction Rates and Chemical Equilibrium) Consider the chemical equation in equilibrium. A(g) + 2B(g) mc030-1.jpg C(g) + D(g) + heat What will happen to the equilibrium of this reaction if the temperature is increased? ------ CORRECT ANSWER---------------B) It will shift to the left because heat is absorbed. (Reaction Rates and Chemical Equilibrium) Which definition describes activation energy? ------CORRECT ANSWER---------------D) the minimum energy that a set of reactants must attain before reaction can occur (Reaction Rates and Chemical Equilibrium) Consider the reaction. mc018-1.jpg At 298 K, the equilibrium concentration of O2 is 1.6 x 10-2 M, and the equilibrium concentration of O3 is 2.86 x 10-28 M. What is the equilibrium constant of the reaction at this temperature? ------CORRECT ANSWER---------------A) 2.0 * 10^-50 (Reaction Rates and Chemical Equilibrium) Consider the reaction pathway graph below. mc021-1.jpg What is represented by D in the graph? ------CORRECT ANSWER---------------A) the activation energy (Reaction Rates and Chemical Equilibrium) What overall effect does adding a catalyst have on a chemical reaction? ------ CORRECT ANSWER---------------B) It speeds up the reaction (Reaction Rates and Chemical Equilibrium) Consider the reaction pathway graph below. mc020-1.jpg Which of the following explains the importance of the activation energy acting as a barrier for reactants? ------CORRECT ANSWER---------------A) It prevents most reactions from occurring spontaneously. (Reaction Rates and Chemical Equilibrium) Which statement is usually true about the relationship between activation energy and reaction rates? ------CORRECT ANSWER---------------B) High activation energy barriers result in low rates. (Reaction Rates and Chemical Equilibrium) Consider the reaction below. H2(g) + CO2(g) mc013-1.jpg H2O(g) + CO(g) At equilibrium at 600 K, the following are true. [CO2] = 9.5 x 10-4 M [H2] = 4.5 x 10-2 M [H2O] = 4.6 x 10-3 M [CO] = 4.6 x 10-3 M What is the value of the equilibrium constant for this reaction in correct scientific notation? ------CORRECT ANSWER---------------C) 4.9 x 10-1 (Reaction Rates and Chemical Equilibrium) Which statement best describes the use of catalytic converters in automobiles? ------ CORRECT ANSWER---------------B) They oxidize hydrocarbons to form less toxic gases. (Reaction Rates and Chemical Equilibrium) According to Le Chatelier's principle, a change in pressure affects the chemical equilibrium of the reaction system under what condition? ------CORRECT ANSWER------ ---------C) Some of the reactants or the products are in the gaseous phase. (Reaction Rates and Chemical Equilibrium) Which statement best describes how dynamic equilibrium relates to a saturated solution of sodium chloride? ------CORRECT ANSWER---------------C) Each second, the amount of solid sodium chloride that dissolves equals the amount of solid sodium chloride that recrystallizes. (Energy in Chemical Reactions) (Energy in Chemical Reactions) A sample of octane (C8H18) that has a mass of 0.750 g is burned in a bomb calorimeter. As a result, the temperature of the calorimeter increases from 21.0°C to 41.0°C. The specific heat of the calorimeter is 1.50 J/(g • °C), and its mass is 1.00 kg. How much heat is released during the combustion of this sample? Use mc021-1.jpg ------CORRECT ANSWER---------------B) 30.0 kJ (Energy in Chemical Reactions) Reactant P contains 50 J of energy, and reactant Q contains 35.3 J of energy. The reactants combine to form product PQ, which contains 104 J of energy. What is the energy transformation? ------CORRECT ANSWER---------------A) Energy is absorbed because the product has more energy than the reactants have. (Energy in Chemical Reactions) Which diagram is a bomb calorimeter? ------CORRECT ANSWER---------------B) (Enthalpy in Chemical Reactions and Phase Changes) Which energy change takes place when gasoline evaporates from a fuel gas can? ------ CORRECT ANSWER---------------B) Energy is absorbed. (Enthalpy in Chemical Reactions and Phase Changes) The molar heat of fusion for water is 6.01 kJ/mol. How much energy is released when 36.8 g of water freezes at its freezing point? Use mc030-1.jpg. ------CORRECT ANSWER---------------B) 12.3 kJ (Enthalpy in Chemical Reactions and Phase Changes) The overall change in enthalpy of a reaction depends only on ------CORRECT ANSWER---------------A) the reactants and the products. (Enthalpy in Chemical Reactions and Phase Changes) Which type of reaction is always spontaneous? ------CORRECT ANSWER---------------A) an exothermic reaction that has an increase in disorder (Enthalpy in Chemical Reactions and Phase Changes) What is the definition of entropy? ------CORRECT ANSWER---------------B) a measure of the overall disorder of a system (Enthalpy in Chemical Reactions and Phase Changes) Consider the following intermediate chemical equations. mc014-1.jpg What is the enthalpy of the overall chemical reaction mc014-2.jpg? ------CORRECT ANSWER---------------B) -1,300 kJ (Enthalpy in Chemical Reactions and Phase Changes) The molar heat of fusion of gold is 12.550 kJ mol-1. At its melting point, how much mass of melted gold must solidify to release 235.0 kJ of energy? Use mc014-1.jpg. ------CORRECT ANSWER---------------D) 3,688.3 g (Enthalpy in Chemical Reactions and Phase Changes) Which energy changes are associated with a liquid freezing? ------CORRECT ANSWER---------------C) Energy is released as potential energy decreases. (Enthalpy in Chemical Reactions and Phase Changes) What is mc032-1.jpgGsystem for the system that is described by the following data? mc032-2.jpgHsystem = -345 kJ, T = 293 K, mc032-3.jpgSsystem = 465 J/K mc032-4.jpgGsystem = mc032-5.jpgHsystem - Tmc032-6.jpgSsystem ------CORRECT ANSWER---------------A) -481 kJ (Enthalpy in Chemical Reactions and Phase Changes) Consider the following equation. Fe2O3(s) + 3H2(g) mc020-1.jpg 2Fe(s) + 3H2O(g) mc020-2.jpgH = 98.8 kJ, and mc020-3.jpgS = 141.5 J/K. Is this reaction spontaneous or nonspontaneous at high and low temperatures? ------CORRECT ANSWER--------------- A) spontaneous at high temperatures, nonspontaneous at low temperatures (Enthalpy in Chemical Reactions and Phase Changes) According to the enthalpy diagram below, which of the following statements is true? mc026-1.jpg Arrows A and D represent the enthalpy of the intermediate chemical reactions. ------ CORRECT ANSWER---------------C) Arrow C indicates that the third intermediate reaction is exothermic. (Enthalpy in Chemical Reactions and Phase Changes) Consider the chemical equation in equilibrium. According to Hess's law, if a series of intermediate reactions are combined, the enthalpy change of the overall reaction is ------CORRECT ANSWER---------------B) the sum of the enthalpy changes of the intermediate reactions. (Final Review) Which is true about reaction rates? ------CORRECT ANSWER---------------D) Reaction rates are not related to spontaneity. (Final Review) Which best characterizes a crystal? ------CORRECT ANSWER---------------B) a dense substance that is hard and incompressible (Final Review) Consider the equation for the formation of water. 2H2 + O2 mc009-1.jpg 2H2O What is the theoretical yield of H2O if 130 g of H2O is produced from 18 g of H2 and an excess of O2? ------CORRECT ANSWER---------------D) 160 g