CHEM 120 Final Exam| 171 Questions| With Complete Solutions

How many bonds can nitrogen have? Which rule or principle should be used? A) Five bonds; octet rule. B) Three bonds; octet rule. C) Three bonds; the Hund's rule. D) Five bonds; the Aufbau Principle. correct answer: B When two hydrogen atoms meet, they will attract to each other and form a bond (and a H2 molecule). Why? A) Because electrons like to stay together. B) Because electrons like to be paired up. C) Because there is attraction between the electron in one hydrogen atom and the nucleus of another hydrogen atom. D) Gravitational attraction between two atoms binds two hydrogen atoms (or any two atoms) together into a molecule. correct answer: C How do you determine the number of electron domains on the central atom? A) Draw Lewis structure of the compound, then add up the numbers of lone electron pair, single bond, double bond, and triple bond. B) The # of electron domains = the # of valence electrons C) The # of electron domains = the number of atoms the central atom is bonded to. D) The # of electron domains = the # of valence electrons divided by 2 correct answer: A Indicate partial charges on each atom of the following two bonds: C-Br and O-N. A) Carbon has partial negative charge and bromine has partial positive charge; both oxygen and nitrogen have no charge. B) Carbon has partial positive charge and bromine has partial negative charge; oxygen has partial negative charge and nitrogen has partial positive charge. C) Carbon has partial negative charge and bromine has partial positive charge; oxygen has partial positive charge and nitrogen has partial negative charge. D) Carbon has partial positive charge and bromine has partial negative charge; oxygen has partial positive charge and nitrogen has partial negative charge. correct answer: B In which of the above structures, the nitrogen atom carries a negative formal charge? A) a B) b C) c D) d correct answer: A In which of the above Lewis structures, the oxygen atom carries a positive formal charge? A) a B) b,c C) a,d D) c E) d correct answer: B Which of the following compounds exists? A) CH3CH3CH3 B) (CH3) 2CCH3 C) CH3CHCH2CH3 D) (CH3)2CHCH3 correct answer: D Indicate hybridization of oxygen atom in the following compounds: H2O, H2C=O, H3O+, HO-, and CO A) sp3, sp3, sp3, sp3, sp B) sp3, sp2, sp2, sp, sp C) sp3, sp2, sp3, sp3, sp D) sp, sp2, sp2, sp, sp correct answer: C Indicate hybridization of carbon in the above compounds. A) sp3, sp2, sp3, sp2 B) sp3, sp2, sp2, sp2 C) sp3, sp3, sp3, sp2 D) sp3, sp3, sp3, sp3 correct answer: A What is the bond angle in a perfect tetrahedron molecule like CH4? A) 120 B) 0 C) 180 D) 109.5 correct answer: D When SO3 reacts water, sulfuric acid (H2SO4) is formed. Is SO3 a BrØnsted-Lowry acid? A) No, it is not a BrØnsted-Lowry acid. B) Yes, it is a BrØnsted-Lowry acid. correct answer: A Conjugate acid and base is a concept unique to BrØnsted-Lowry acids and bases. Which of the pairs below are not conjugate acid and base? a. H2SO4 and SO42- b. H2CO3, CO2 c. HCl and Cl2