4) Interpret in words the equation: P4O10 (s) + 6 H2O (l) 4 H3PO4 (aq)

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1 CHEM102 Chemistry II Spring Mid-term Exam/Faculty of Agricultural Sciences and Technologies Student Registration No: Instructor: Prof.Dr.Hüseyin Oğuz Student Name-Surname: Dept. of Computer Information Systems Room#: AS 014 Date: /14:30-16:00 1) In a chemical reaction 1) A) there are equal numbers of atoms on each side of the reaction arrow. B) there are always the same number of products as there are reactants. C) there are equal numbers of molecules on each side of the reaction arrow. D) the number of atoms depends present in a reaction can vary when the conditions change during the reaction. E) none of the above 2) Which reaction is not an example of a redox reaction? 2) A) 2 Hg (l) + O2 (g) 2 HgO (s) B) 6 HCl (aq) + 2 Al (s) 2 AlCl3 (aq) + 3 H2 (g) C) 2 Al2O3 (s) 4 Al (s) + 3 O2 (g) D) 2 (NH4)3PO4 (aq) + 3 Ba(NO3)2 (aq) Ba3(PO4)2 (s) + 6 NH4NO3 (aq) E) CH4 (g) + 2 O2 (g) CO2 (g) + 2 H2O (g) 3) Which is the correct equation for the reaction of magnesium with hydrochloric acid to produce hydrogen and magnesium chloride? A) Mg + HCl H + MgCl B) Mg + 3 HCl 3 H + MgCl2 C) Mg + 2 HCl 2 H + MgCl2 D) 2 Mg + 6 HCl? 3 H2 + 2 MgCl2 E) Mg + 2 HCl H2 + MgCl2 4) Interpret in words the equation: 3) 4) P4O10 (s) + 6 H2O (l) 4 H3PO4 (aq) A) Zero moles of solid phosphoric oxide dissolve in six moles of water to produce four moles of phosphorous acid. B) One mole of phosphorus(x) oxide combines with six moles of water to produce four moles of solution of hydrogen phosphate. C) One mole of solid tetraphosphorus decaoxide reacts with six moles of liquid water to produce four moles of phosphoric acid solution. D) Four moles of solid phosphorus, five moles of diatomic oxygen gas, and six moles of liquid water react together to produce four moles of phosphoric acid in solution. E) Four atoms of phosphorus, 16 atoms of oxygen, and 12 atoms of hydrogen rearrange to produce four molecules of phosphoric acid. 5) Which one of the following substances is produced during an acid/base (or neutralization) reaction? A) NaOH B) H2 C) H2O D) CO2 E) NaCl 6) When the reaction shown is correctly balanced, the coefficients are 5) 6) Li + Br2 LiBr

2 A) 2, 1, 2 B) 1, 2, 2 C) 1, 2, 1 D) 2, 2, 1 E) 1, 1, 1 7) Which sample contains the smallest number of atoms? 7) A) 3.0 mol Cl2 B) 2.0 mol CH4 C) 2.5 mol Au D) 1.5 mol NaCl E) 1.0 mol H2O 8) How many molecules are there in 3.00 moles of NH3? 8) A) B) C) 3.00 D) 1.00 E) ) The scientific principle which is the basis for balancing chemical equations is 9) A) the Law of Definite Proportions. B) Avogadro's Law. C) the Law of Conservation of Energy. D) the Law of Conservation of Mass. E) the Law of Conservation of Mass and Energy. 10) A thimble of water contains 4.0 x 1021 molecules. The number of moles of H2O is: 10) A) 2.4 x 1045 B) 2.4 x 1023 C) 6.6 x D) 2.4 x E) 6.6 x ) N2 + O2 2 NO ΔH = 43.2 kcal 11) Based on the reaction shown, which statement is true? A) 43.2 kcal are consumed when 1.00 g of O2 reacts. B) 43.2 kcal are consumed when 1.00 mole of O2 reacts. C) 43.2 kcal are consumed when 1.00 g of NO is produced. D) 43.2 kcal are produced when 1.00 mole of NO is produced. E) 43.2 kcal are consumed when 1.00 g of N2 reacts. 12) The position of the equilibrium for a system where K = can be described as being favored to ; the concentration of products is relatively. A) the left; large B) the left; small C) the right; small D) the right; large E) neither direction; large 13) S + O2 SO kcal 12) 13) Based on the reaction shown, which statement is true?

3 A) 70.8 kcal are consumed when 1 g of sulfur reacts. B) 70.8 kcal are produced when 1 g of sulfur dioxide is produced. C) 70.8 kcal are produced when 1 g of sulfur reacts. D) 70.8 kcal are produced when 32.1 g of sulfur reacts. E) 70.8 kcal are consumed when 32.1 g of sulfur reacts. 14) Consider the reaction shown: 14) P4 (s) + 10 Cl2 (g) 4 PCl5 (s) kcal When g of P4 react, kcal will be. A) 452; produced B) 729.7; produced C) 452; consumed D) 182.4; produced E) 182.4; consumed 15) Which of the following conditions characterizes a system in a state of chemical equilibrium? 15) A) Concentrations of reactants and products are equal B) Reactant molecules no longer react with each other C) Reactants are being consumed at the same rate they are being produced D) Rate of forward reaction has dropped to zero E) Product concentrations are greater than reactant concentrations 16) Consider the reaction shown: 16) 2 CO (g) + O2 (g) CO2 (g) kcal This reaction is because the sign of ΔH is. A) exothermic; positive B) exothermic; neither positive nor negative C) exothermic; negative D) endothermic; negative E) endothermic; positive 17) P4 (s) + 10 Cl2 (g) 4 PCl5 (s) ΔH = kcal 17) Based on the reaction shown, which statement is true? A) When 1 mol P4 (s) reacts, kcal are released. B) When g P4 (s) react, kcal are released. C) When g PCl5 (s) are produced, kcal are consumed. D) When 1 mol PCl5 (s) is produced, kcal are released. E) When g P4 (s) react, kcal are consumed. 18) Consider the reaction: 18) A + 2 B 2 C + D The equilibrium expression for this reaction is A) B) C) D) E)

4 19) All of the statements regarding the symbol "ΔH" are correct except 19) A) it can be called entropy change. B) it has a negative value for an exothermic reaction. C) it can be called heat of reaction. D) it represents the difference between the energy used in breaking bonds and the energy released in forming bonds in a chemical reaction. E) it can be called enthalpy change. 20) 4 PCl3 (l) P4 (s) + 6 Cl2 (g) ΔH = kcal 20) Based on the reaction shown, which statement is true? A) When 1 mol PCl3 (l) reacts, kcal are released. B) When g P4 (s) are produced, kcal are released. C) When g PCl3 (l) react, kcal are consumed. D) When 1 mol P4 (s) is produced, kcal are consumed. E) When g PCl3 (l) react, kcal are released. 21) What is the normality of a solution containing 100. g HNO3 in 500. ml of solution? 21) A) 1.59 N B) N C) N D) 3.17 N E) 1.26 N 22) The base forms a new bond in a Brønsted-Lowry acid-base reaction. 22) A) ionic B) covalent C) metallic D) aquo E) hydrogen 23) What is the conjugate base of water? 23) A) H3O+ (aq) B) H+ (aq) C) H2O (l) D) O2 - (aq) E) OH- (aq) 24) What is the concentration of a solution of HCl in which a 10.0 ml sample of acid required 50.0 ml of M NaOH for neutralization? A) M B) 7.50 M C) M D) M E) M 24) 25) What is the hydrogen ion concentration in a solution with ph = 2.34? 25) A) M B) M C) M D) M E) M 26) In an aqueous solution that is basic, [H3O+] is than and than [OH-]. A) greater; greater B) less; greater C) less; less D) greater; less E) none of the above 27) The ph of a cup of coffee is measured as Express this measurement as [H+], using the correct number of significant figures. A) M B) M 26) 27)

5 C) M D) M E) M 28) Which of the following compounds is a salt? 28) A) NH4NO3 B) C6H6 C) NH3 D) CH3CO2H E) Al(OH)3 29) The [OH-] and the ph of M KOH at 25 C are respectively: 29) A) and B) M and C) M and D) M and E) M and ) Which of the following cannot act as a Brønsted base? 30) A) NH3 B) NH2 - C) NH4 + D) CO3 2- E) HCO3-31) Monochlorination of pentane, C5H12, leads to formation of how many different products? 31) A) 3 B) 5 C) 4 D) 2 E) 1 32) In straight-chain alkanes, the carbon atoms on each end of the molecule always form bonds with atoms of hydrogen; the carbons within the molecule always form bonds with hydrogen atoms. A) 4; 4 B) 4; 2 C) 3; 2 D) 2; 2 E) 3; 3 32) 33) What is the IUPAC name of the compound shown? 33) A) 2-ethyl-2-methylpentane B) 2,2-ethyl-methylpentane C) 3,3-dimethylhexane D) isooctane E) 2-methyl-2-propylbutane 34) The name of the hydrocarbon with three carbon atoms and having only single bonds between carbon atoms is A) decane. B) methane. C) ethane. D) butane. E) propane. 34) 35) The various shapes taken on by an organic molecule are known as. 35) A) constitutional isomers B) configurations C) conformations

6 D) preferential isomers E) none of the above 36) Which atom is most likely to form a polar covalent bond with carbon? 36) A) S B) C C) O D) H E) Na 37) What is the minimum number of carbons that must be present in a molecule to have a secondary carbon? A) 2 B) 3 C) 5 D) 1 E) 4 37) 38) What is the IUPAC name of the compound shown? 38) A) dimethylbutane B) hexane C) 2,2-dimethylbutane D) isohexane E) ethylmethylpropane 39) Describe the unique characteristics of carbon that make it the basis of such a large number of organic compounds. 39) 40) Which molecule is not an isomer of the molecule shown? 40) O A) B) C) OH D) C O C C C E) 41) Which of the following compounds is a saturated hydrocarbon? 41) A) 1,3-butadiene B) hexane C) benzene D) acetylene E) ethylene 42) Which of the following alkenes can exhibit cis-trans isomerism? 42)

7 A) 1-pentene B) 3-octene C) 1,1-dibromobutene D) 2-methyl-2-octene E) none of these 43) Which molecule represents 4-ethyl-2-hexyne? 43) A) (CH3CH2)2CHC CCH(CH2CH3)2 B) (CH3CH2)2CHC CCH3 C) CH3CH2CH2CH2C CCH3 D) CH3CH2C CCH2CH2CH3 E) CH3CH2CH2C CCH3 44) The starting material for polymerization reactions is a(an) 44) A) isomer. B) dimer. C) catalyst. D) monomer. E) alkane. 45) The commonly accepted mechanism for explaining alkene reactions involves formation of 45) A) carbanions. B) carbocations. C) carbon atoms with 10 electrons. D) carbon atoms with four electrons. E) carbon atoms which have lost all their electrons. 46) Which of the following is not the common name of an aromatic compound? 46) A) phenol B) xylene C) aniline D) toluene E) acetone 47) The term delocalization means "not limited to a particular place or area." Explain how this term describes the behavior of electrons in aromatic compounds. 47) 48) The most common reactions involving aromatics are reactions. 48) A) addition B) oxidation C) elimination D) substitution E) reduction 49) The process used to produce simple alkenes is 49) A) cracking of alkanes. B) polymerization of monomers. C) smelting of ores. D) condensation of small molecules. E) distillation of crude oil. 50) When 2-butene reacts completely with bromine, the product is 50) A) 1,2-dibromobutane. B) 1,3-dibromobutane. C) 2,3-dibromobutane. D) 2-bromobutane. E) 3-bromobutane.

8 1) A 2) D 3) E 4) C 5) C 6) A 7) C 8) B 9) D 10) E 11) B 12) B 13) D 14) D 15) C 16) C 17) A 18) C 19) A 20) D 21) D 22) B 23) E 24) D 25) D 26) C 27) C 28) A 29) A 30) C 31) A 32) C 33) C 34) E 35) C 36) C 37) B 38) C 39) It has four valence electrons and is a very small atom, so it always forms four strong covalent bonds. It bonds with other carbon atoms to form long chains or rings. 40) C 41) B 42) B 43) B 44) D 45) B 46) E 47) In a benzene ring, the six carbon atoms are often drawn in a ring with alternating single and double bonds between them. Another drawing shows a hexagon with a circle inside. In both cases, the six electrons not involved in the single bonds are thought to move freely around the ring, not really belonging to any particular pair of carbon atoms. This delocalization of electrons explains the observations that all the carbon-carbon bonds are the same

9 lengt and that aromatics do not undergo addition reactions as would be expected if the extra electrons were localized. h The delocalization of electrons stabilizes the ring system. 48) D 49) A 50) C