Q&A Hero

Q: All the following are examples of chemical changes except A) aging. B) photosynthesis. C) fermentation. D) perspiration. E) respiration.

Q: Which of the following statements is not correct? A) The combustion of methane (a component of natural gas) is a chemical change. B) The melting of ice is a physical change. C) The dissolution of sugar in water is a chemical change. D) The decomposition of sugar into carbon and water when mixed with sulfuric acid is a chemical change. E) The evaporation of gasoline is a physical change.

Q: Which of the following is a homogeneous mixture? A) gasoline B) vegetable oil and water C) sugar dissolved in water D) A and C E) A, B, and C

Q: All of the following are homogeneous mixtures except A) sodium chloride and potassium chloride. B) hydrogen gas and chlorine gas. C) sodium chloride and potassium chloride solution. D) mercury-zinc solution. E) hydrochloric acid solution.

Q: All of the following are examples of mixtures except A) supermarket salt. B) distilled water. C) soft water. D) hard water. E) drugstore hydrogen peroxide.

Q: Heating a certain pure solid completely decomposes it into a solid and a gas, each of which is also a pure substance. Which of the following is/are reasonable conclusions regarding these observations? 1) The solid is a compound and the gas is an element. 2) At least one of the products is an element. 3) The original solid is not an element. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: A clear colorless liquid in an open beaker was heated to boiling. The liquid began to boil at 110ºC, and as vapors escaped, the temperature of boiling gradually increased to 115ºC, at which point the heating was stopped. On the basis of this information, we can say that the material in the beaker was aA) pure compound.B) homogeneous solution.C) pure substance.D) pure element.E) heterogeneous solution.

Q: Which of the following is a mixture? A) a homogeneous solution of sugar dissolved in water B) bromine (a liquid with the formula Br2) C) sucrose (table sugar: the formula is C12H22O11) D) graphite (an allotrope of carbon) E) calcium oxide (CaO or lime)

Q: A solution is a A) pure element. B) pure mixture. C) heterogeneous mixture. D) homogeneous mixture. E) pure compound.

Q: A sample that cannot be separated into two or more substances by physical means is A) a heterogeneous mixture. B) a compound. C) either a compound or an element. D) an element. E) a homogeneous mixture.

Q: Two types of pure substances are A) compounds and heterogeneous solutions. B) compounds and elements. C) elements and homogeneous solutions. D) compounds and homogeneous solutions. E) elements and heterogeneous solutions.

Q: The state of matter for an object that has a definite volume but not a definite shape is the A) elemental state. B) gaseous state. C) mixed state. D) liquid state. E) solid state.

Q: The state of matter for an object that has both definite volume and definite shape is the A) gaseous state. B) solid state. C) mixed state. D) elemental state. E) liquid state.

Q: After a certain chemical reaction has completed, it is found that 33.7g of product was produced. According to the law of conservation of mass, which statement must be true? A) The total mass consumed of all reactants was 33.7g. B) The mass consumed of each reactant was 33.7g. C) The mass of reactants consumed depends on the number of reactants present. D) Before the reaction started, there was 33.7g total of all reactants. E) Before the reaction started, there was 33.7g of each reactant.

Q: Sodium oxide reacts with water to produce sodium hydroxide. Suppose 18.6g of sodium oxide is combined with 33.7g of water. When the reaction is complete, all the sodium oxide has been consumed. According to the law of conservation of mass, which is a true statement? A) The mass of sodium hydroxide produced must equal 52.3g. B) The mass of unreacted water must equal 15.1g. C) The mass of sodium hydroxide produced must equal 18.6g. D) The mass of water consumed must equal 18.6g. E) The mass of sodium hydroxide produced plus the mass of unreacted water must equal 52.3g.

Q: A sample of rubidium carbonate, weighing 7.00 g, requires 2.20 g of hydrogen chloride gas to completely decompose to water, rubidium chloride, and carbon dioxide gas. The total mass of water and rubidium chloride formed is 7.90g and no hydrogen chloride or rubidium carbonate remains. According to the law of conservation of mass, what mass of carbon dioxide must have been formed? A) 1.30 g B) 0.90 g C) 8.65 g D) 17.10 g E) 3.07 g

Q: A 5.77g sample of calcium carbonate completely decomposes into calcium oxide (lime) and carbon dioxide gas when heated. If 3.23 g calcium oxide is produced, what mass of carbon dioxide must have been formed? A) 2.54 g B) 9.00 g C) 18.65 g D) 0.56 g E) 1.92 g

Q: In a certain chemical reaction, 7.29g of compound A is added to 5.70g of compound B. Once the reaction is complete, 3.60g of compound A and 1.17g of compound B remain. What mass of products was produced? A) 17.76 g B) 4.53 g C) 8.22 g D) 3.69 g E) 4.77 g

Q: A sample of silicon is burned in oxygen to form silicon dioxide. What mass of oxygen is consumed if 57.76 g silicon dioxide is formed from 27.00 g silicon? A) 30.76 g B) 84.76 g C) 1559.59 g D) 0.47 g E) none of the above.

Q: A 19.0-g sample of lithium is completely burned in air to form lithium oxide. The mass of lithium oxide must be A) less than 19.0 g. B) greater than 19.0 g. C) equal to 19.0 g. D) all of the above. E) none of the above.

Q: A saline solution similar to that used for intravenous drips is made by dissolving 0.45 g sodium chloride in 50.00 g water. Which of the following statements concerning the saline solution and the law of conservation of mass is/are correct? 1) The mass of the saline solution is greater than the mass of water. 2) The mass of the saline solution is equal to the combined mass of sodium chloride and water. 3) The mass of the saline solution is greater than the mass of the sodium chloride. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: Which of the following statements concerning experiment and explanation is/are true?1) A law is always given in the form of a mathematical expression.2) Once a hypothesis passes one or two tests it is considered a theory.3) Observation is a key component of the scientific method.A) 1 onlyB) 2 onlyC) 3 onlyD) 1 and 2E) 1, 2, and 3

Q: An untested explanation of a series of experimental observations is called _____. A) a hypothesis B) a theory C) a law D) an experiment E) the scientific method

Q: What is a scientific theory? A) It is a collection of experimental data. B) It is an assertion of scientific fact. C) It is a guess or conjecture about natural phenomena. D) It is a fundamental relationship of nature. E) It is an explanation of natural phenomena that has undergone significant testing.

Q: What is the IUPAC name for the following compound? A) 1, 3-dimethyl-1-ethylhexane B) 4, 6-dimethyl-6-ethylhexane C) 3, 5-dimethyloctane D) sec-hexylbutane

Q: What is the IUPAC name for the continuous carbon chain of C10H22? A) decane B) dipentane C) tenalkane D) tenane

Q: What is the IUPAC name for the following compound? A) heptane B) 3, 3-dimethylpentane C) 2, 2-dimethyl-2-ethylpropane D) 2, 2-diethylpropane

Q: ________ is the means by which information in DNA is transferred to and decoded by RNA. ________ is the means by which RNA uses information to build proteins.

Q: (CH3)2CH represents a butyl group. A) normal B) secondary C) tertiary D) quaternary

Q: The four cyclic amine bases that occur in DNA are ________, ________, ________, and ________.

Q: What is the name for the alkyl group: A) isobutyl B) tert-butyl C) tributyl D) trimethyl

Q: Naturally occurring organic molecules that dissolve in nonpolar solvents are called ________ of which the most plentiful in nature are ________ and ________.

Q: If the point of attachment to an alkane is by the middle carbon in a propyl group, the group is called A) isopropyl. B) n-propyl. C) sec-propyl. D) tert-propyl.

Q: Monosaccharides are classified as either ________ or ________.

Q: An alkyl group is named for the part of the alkane group that remains after a ________ is removed. A) C atom B) CH3 group C) CH2 group D) H atom

Q: Individual amino acids that make up a protein are called ________.

Q: Which statement below is false concerning nomenclature rules for alkanes? A) Carbon atoms are numbered starting with the atom farthest from the branching point. B) Each branching group is assigned a number referring to its point of attachment in the parent chain. C) The name of the alkane is written as a single word. D) The parent name is taken from the longest continuous chain of carbon atoms.

Q: The amide bonds that form when two or more amino acids link together are called ________ bonds.

Q: The functional groups in the molecule below are O O   HCCH2COCH3 A) alkane, aldehyde, and ester. B) alkane, aldehyde, ketone, and ether. C) alkane, carboxylic acid, and ester. D) alkane, ketone, and ester.

Q: Reaction sequences that break molecules apart are known as ________, while reaction sequences in which larger molecules are created are known as ________.

Q: The functional groups in the molecule below are H2NCH2CO2H A) alkane, amide, and carboxylic acid. B) alkane, amine, and carboxylic acid. C) alkane, amide, ketone, and alcohol. D) alkane, amine, ketone, and alcohol.

Q: The molecule CH3CH2CO2CH2CO2H contains an ________ functional group and a ________ functional group.

Q: Which one of the following compounds is an alcohol? A) CH3OCH3 B) CH3COCH3 C) (CH3)2CHOH D) CH3CO2H

Q: The molecule H2NCH2CH2CH2OH contains an ________ functional group and an ________ functional group.

Q: Which functional group below represents an aldehyde? A) B) C) D)

Q: C2H6O is the empirical formula for both ethyl alcohol, CH3CH2OH and dimethyl ether, CH3OCH3. In order to boil CH3CH2OH the strongest intermolecular forces that must be overcome are (London dispersion, dipole-dipole, hydrogen bonding) forces. In order to boil CH3OCH3 the strongest intermolecular forces that must be overcome are (London dispersion, dipole-dipole, hydrogen bonding) forces. Which compound is expected to have the higher boiling point?

Q: Which functional group below represents a ketone? A) B) C) D)

Q: When toluene C6H5CH3 is reacted with Br2/FeBr3, the number of different products that can be formed is ________.

Q: Which functional group below represents a carboxylic acid? A) B) C) D)

Q: The cycloalkane represented by a hexagon is named ________ and has the molecular formula ________.

Q: Identify the functional group: A) aldehyde B) ketone C) ester D) ether

Q: In the dark the reaction of 2-pentene with chlorine will form how many different products?

Q: Identify the functional group: A) alcohol B) amine C) amide D) ester

Q: The molecules , respectively, belong to the ________ family and the ________ family of organic molecules.

Q: Which of the following statements is false regarding functional groups? A) The chemical properties of the functional group dictate the chemistry of the larger molecule. B) Each functional group has a characteristic chemical behavior. C) A functional group consists of an atom or a group of atoms that is part of a larger molecule. D) A functional group consists of only carbon and hydrogen atoms.

Q: What is the empirical and molecular formulas of 1-tert-butyl-2-methylcyclopropane?

Q: When alkanes react with chlorine in the presence of ultraviolet light, chlorine atoms substitute for one or more alkane hydrogen atoms. What is the number of different chloroalkane compounds that can be formed by the reaction of C2H6 with chlorine? A) 3 B) 6 C) 9 D) 12

Q: represents a ________ (normal, secondary, tertiary) butyl group.

Q: Some of the products from reaction of bromine and propane are shown below. (The hydrogen atoms are not shown in the structures.) How many are identical structures? A) 2 B) 3 C) 4 D) All are isomers of each other.

Q: The alkane, 3-ethyl-3-methylhexane contains ________ carbon atoms and ________ hydrogen atoms.

Q: Which one of the structures below is different from the other three? A) I B) II C) III D) IV

Q: The IUPAC name for the alkane shown below is ________.

Q: Which of the structures below are identical? A) I and II B) II and III C) III and IV D) I and IV

Q: The condensed formula of the smallest molecule that contains the ether functional group is ________.

Q: Which of the following condensed structures represent the same molecule? A) I and II B) II and IV C) III and IV D) II and III

Q: The combustion of methane has a standard enthalpy of combustion H = -802 kJ per mole of methane burned. How many kilojoules of heat are released if 1.28 grams of oxygen are consumed in the reaction?

Q: Which condensed structure below representing an alkane is not correct? A) CH3CH2CH3 B) C) CH3CH2CH2CH3 D)

Q: The number of different monochloro substitution products (C5H11Cl) that can form from the reaction of 2,2-dimethylpropane with Cl2 is ________.

Q: Which is the condensed structure of a straight-chain hydrocarbon? A) I B) II C) III D) IV

Q: The number of different monochloro substitution products (C5H11Cl) that can form from the reaction of 2-methylbutane with Cl2 is ________.

Q: Do the two condensed structures (1) and (2) below represent the same or different molecules?

Q: Which of the following statements about isomers is false? A) All alkanes have branched chain isomers. B) As the number of carbon atoms increase in a compound, so do the number of possible isomers. C) Isomers have different physical properties. D) Isomers have the same formula but different molecular structures.

Q: Do the condensed structures shown below represent the same or different molecules?

Q: Compounds that have the same formula but different molecular structures are called A) isoelectronic. B) isomers. C) isotones. D) isotopes.

Q: How many isomers exist for C5H12? Of these isomers, how many are straight-chain isomers and how many are branched isomers?

Q: Which compound is a saturated hydrocarbon? A) benzene B) cyclohexene C) 2-methylpentane D) propylene

Q: The condensed structures for the two isomers of C4H10 are (1) ________ and (2) ________.

Q: Another term for alkanes is A) alkenes. B) alkynes. C) saturated hydrocarbons. D) unsaturated hydrocarbons.

Q: Organic molecules containing only carbon and hydrogen and having only single bonds are called ________ hydrocarbons, or ________.

Q: Which class of hydrocarbons has the general formula CnH2n+2? A) alkanes B) alkenes C) alkynes D) cylcloalkanes