Lehman College Chemistry Exam 1A Fall 2019 PDF

Lehman College of the City University of New York Department of Chemistry 1) If the diagram on the right is meant to illustrate a sample of boiling water, which states of matter are represented in the diagram? a. Liquid an...

Lehman College of the City University of New York Department of Chemistry 1) If the diagram on the right is meant to illustrate a sample of boiling water, which states of matter are represented in the diagram? a. Liquid and gas b. Gas and solid c. Liquid and solid d. Solid, liquid, and gas 2) How many milligrams are in a nanogram? a. 106 mg b. 1012 mg c. 10-6 mg d. 10-12 mg 3) There are 10-9 megagram in 1 _______________. a. gram b. milligram c. microgram d. nanogram 4) Which of the follows particle diagrams best represents a mixture of solid and a gas? a. b. c. d. 5) The fastest land animal is Cheetah. They run at the speed of 120.7 kilometer per hour. What is that speed in feet per minute? (1 mile = 5280 ft, 1 mile = 1.609 km, 1 ft = 12 inches, 1 inch = 2.54cm). Express your result in scientific notation. a. 6.60137 × 10-3 ft/min b. 6.60137 × 103 ft/min c. 6601.37 ×103 ft/min d. 6601.37 ft/min 6) Naturally occurring hydrogen (H) consists of 3 isotopes, 1H, 2H and 3H. Their relative abundances are 99.9800%, 0.0156% and 0.0044%. Which of the following states is true? a. 1H has more protons than 2H. b. 2H has more electrons than 3H. c. 3H has more proton than 2H. d. 3H and 2H have the same number of proton. CHEM 114 1 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry 7) An atom with 19 protons and 18 electrons has a charge of ____ and is called ___________________. a. +1, an anion b. -1, an anion c. +1, a cation d. -1, a cation 8) Which element would have a neutral atom with an electron configuration of [Xe]6S2? a. Ba b. I c. CS d. Rn 9) Consider the Zn2+ ion. What is the correct electron configuration and magnetism? a. [Ar]3d10, diamagnetic b. [Ar]4s23d8, diamagnetic c. [Ar]4S24P63d4, paramagnetic d. [Ar]3d2, diamagnetic 10)Select the list below that includes one s-block metal, two transition metals and one p-block metal, respectively. a. K, Al, S, Br b. Ca, Mo, Hg, Cl c. Sr, Ni, Se, Cl d. Sc, Zn, F, Cl 11)How can you calculate the number of neutrons in an atom of 120Sn2+? a. (mass number) b. ) (mass number – atomic number c. (mass number – atomic number - 2) d. (mass number - atomic number + 2) 12)What is the correct electron configuration for the bromide ion? a. 1s22s22p63s23p64s24p63d9 b. 1s22s22p63s23p64s23d104p6 c. 1s22s22p63s23p64s24p63d10 d. 1s22s22p63s23p64s23d104p5 CHEM 114 2 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry 13) A certain element Si has three isotopes with the following characteristics: Isotope Abundance Isotopic mass 1 92.2297% 27.9769 2 4.6832% 28.9765 3 3.0872% 29.9738 What is the average atomic mass for the element Si? a. 28.0854 b. 28.9757 c. 33.3334 d. 2.80854 14)Within the 2nd period of the periodic table, which elements would be paramagnetic neutral atoms? a. All the elements in that row b. None of the elements in that row c. Li, B, N, F d. Be, C, O, Ne 15) How many total atoms are in one molecule of sucrose if its chemical formula can be written as (C6H11O5)2O? a. 54 b. 45 c. 23 d. 22 16) How many total atoms are in one molecule of sucrose if its chemical formula can be written as (CH2OH)2? e. 6 f. 10 g. 5 h. 4 17)The chemical formula for aluminum sulfate is: a. AlSO4 b. Al2(SO4)3 c. Al3(SO4)2 d. Al(SO4)3 18) The names for transition metal ionic compound, non-transition metal ionic compound, and covalent compound, respectively, are: CHEM 114 3 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry a. Zinc (II) chloride, Strontium sulfate, dinitrogen pentoxide b. Zinc chloride, Strontium (II) sulfate, dinitrogen pentoxide c. Zinc chloride, dinitrogen pentoxide, Strontium (II) sulfate d. Strontium sulfate, Zinc (II) chloride, dinitrogen pentoxide 19)What is the correct name for Mg3(PO4)2? a. Magnesium (II) phosphate b. Magnesium phosphate c. Tri-Magnesium diphosphate d. Phosphate magnesium 20)The chemical formula for chromium (III) sulfate is: a. Cr2(SO4)3 b. Cr2(SO3)3 c. CrSO3 d. CrSO4 21) Which of the following pairs is incorrectly named? a. ZnO, Zinc (II) oxide b. CCl4, Carbon tetrachloride c. Hg2Cl2, Mercury (II) chloride d. N2O5, dinitrogen pentoxide 22) With respect to the given Lewis structure for bromochloroiodomethane (CHBrClI), which halogen substituent has the lowest electronegativity? a. Br b. Cl c. I d. H 23) Consider the following Lewis structure for ozone (O3) proposed by a student in General Chemistry class. Which of the following statements about this structure is correct? a. This is not a valid Lewis structure because the oxygen in the middle shares only 6 electrons. b. This is a valid Lewis structure because the octet rule is satisfied on all oxygen atoms. c. This is not a valid Lewis structure because the bonds are symmetric. d. This is not a valid Lewis structure because there are too many total valence electrons. CHEM 114 4 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry 24) How many total electrons should be included in the Lewis structure for the polyatomic ion sulfate (SO42-)? a. 28 b. 32 c. 30 d. 36 25) How many total valence electrons should be included in the Lewis structure for HCO3-? a. 23 b. 22 c. 24 d. 34 26) With reference to the Lewis structure shown below, which of these statements is correct? a. The C-H bond is the most polar because there are more C-H bonds in the molecule. b. The C-O bond is the most polar because C and O have the greatest difference in electronegativity. c. The C=C bond is the most polar because it is a bond between similar atom. d. The O-H bond is the most polar because H and O have the greatest difference in electronegativity. 27) Examine the provided Lewis structure and then determine which of the following statements about the structure are correct. I. Every atom in this molecule has a complete octet of electrons. II. Every atom in this molecule has at least one lone pair. III. There are 40 valence electrons in this molecule IV. There are 8 shared bonds in this molecule. e. I & IV f. I, III & IV g. I, II, & III h. I, II, & IV 28) Which of the following would have the highest bond energy? a. A nitrogen-nitrogen single bond CHEM 114 5 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry b. A nitrogen-nitrogen double bond c. A nitrogen-nitrogen triple bond d. All these carbon-carbon bonds have the same bond energy. 29) Which of the following statements best explains which Lewis structure shown below is the best choice for CH5N? Structure 1 Structure 2 a. Structure 1 is better because the double bond between C and N is stronger than the single bond in Structure 2. b. Structure 1 is better because it has the correct number of electrons while Structure 2 does not. c. Structure 2 is better because it obeys the octet and duet rules while Structure 1 does not. d. Structure 2 is better because it has the correct number of valence electrons while Structure 1 does not. 30) What is the total sum of coefficients once the following reaction has been properly balanced? ___Ca(s) + ___H2O(l) → ___Ca(OH)2(aq) + ___H2(g) a. 1 b. 2 c. 3 d. 5 31) What is the coefficient of iron oxide (Fe3O4) for the following reaction once it has been properly balanced? ___Al(s) + ___Fe3O4(s) → ___Al2O3(s) + ___Fe(s) a. 8 b. 3 c. 4 d. 24 CHEM 114 6 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry 32) Consider the unbalanced reaction for the decomposition of aluminum oxide at room temperature to produce aluminum and diatomic oxygen shown below. ___Al2O3 (s) → ___Al (s) + ___O2(g) How many dozen of aluminum will be generated when you start with 25 dozen of aluminum oxide. a. 25 dozen b. 37.5 dozen c. 12.5 dozen d. 50 dozen 33) What is the coefficient for potassium sulfate plus iron sulfate in the chemical reaction that occurs when iron(III) sulfate reacts with potassium thiocyanate (KSCN) to produce potassium iron(III) thiocyanate (K3Fe(SCN)6) and potassium sulfate. Fe2(SO4)3 + 12KSCN ➔ 2K3Fe(SCN)6+ 3K2SO4 a. 4 b. 3 c. 2 d. 18 4 34) How many molecules of NH3 can be produced if you react 1.87 x 10 hydrogen (H) atom with an excess of N2? a. 2.81 × 104 b. 1.41 × 104 c. 1.87 × 104 d. 6.23 × 103 20) Consider the Lewis structure for F CO (carbon is the central atom in this structure). Which of 2 the following statements about this Lewis structure is correct? a. The central atom contains no lone pairs of electrons b. Total valence electron is 24 c. The number of shared electron is 8 d. All of the above CHEM 114 7 Fall 2019 Exam 1A  Lehman College of the City University of New York Department of Chemistry 21) The correct names for Mg3(PO4)2, N2O5, and Cr(ClO4)6, respectively, are: a. Magnesium phosphate, dinitrogen pentoxide, chromium perchlorate b. Magnesium phosphate, dinitrogen pentoxide, chromium (VI) perchlorate c. Magnesium (II) phosphate, dinitrogen pentoxide, chromium (VI) perchlorate d. Magnesium phosphate, nitrogen (V) oxide, chromium (VI) chlorate 35) According to the following balanced chemical reaction, how many molecules of nitric oxide (NO) are formed form 100 molecules of ammonia (NH3)? 4NH3 + 5O2 → 4NO + 6H2O a. 6 b. 12 c. 18 d. 100 36) What is the coefficient for hydrogen in the following reaction when properly balanced? H2 (g) + F2 (g) → 2HF (g) a. 1 b. 2 c. 3 d. 6 37) What is the total coefficient for chemical equation that represents the reaction between aluminum hydroxide and sulfuric acid, which form aluminum sulfate and water? 2Al(OH)3 + 3H2SO4 → Al2(SO4)3 + 6H2O a. 2 b. 3 c. 6 d. 12 38) Consider the following reaction: Heat + O2(g) + N2(g) → 2NO(g) What can we say about the energy of the system? a. ΔH>0 b. ΔH=0 c. ΔH