Page 1 of 5 Student ID : _________________________ CH 115 Summer 2014 Mock Exam 1 *** Assume that equations are NOT balanced *** Multiple choice (5 points each, no partial credit) 1. What is the percent composition of oxygen in phosphate? a. 60.7% b. 80.0% c. 56.3% d. 16.8% e. 67.4% 2. Which of the following lists include a halogen, an alkaline earth metal and a noble gas (in any order)? a. Ba, Na, Ca b. Ti, Ni, Li c. Xe, Se, Be d. Zr, Sr, Kr e. Mg, Ag, Hg 3. Which of the following reactions are displacements? X. 2 Mg(s) + O2(g) → 2 MgO(s) Y. 2 Li(s) + BaCl2(aq) → 2 LiCl(aq) + Ba(s) Z. CaCl2(aq) + K2CO3(aq) → CaCO3(s) + 2 KCl(aq) a. X and Y b. Y and Z c. Z only d. Y only e. X only 4. Calculate the atomic weight of a sample of iron that is 28.5% 56Fe and 71.5% 60Fe. a. 56.4 amu b. 55.8 amu c. 59.3 amu d. 60.4 amu e. 67.4 amu 5. Given 2.435 mol of C21H30O2, how many grams do you have? a. 0.07 g b. 314 g c. 766 g d. 250 g e. 43.0 gPage 2 of 5 6. Which statements are false? X. According to the atomic theory all matter is composed of atoms. Y. Compounds are formed by the chemical combination of two or more atoms (e.g. O2 is a compound). Z. The mass of neutrons is negligible because they are much less massive than protons and electrons. a. X and Y b. Z only c. X only d. X and Z e. Y and Z 7. Given 55.0 g of Cu, how many atoms do you have? a. 6.02 x 1023 atoms b. 3.31 x 1023 atoms c. 5.21 x 1023atoms d. 4.76 x 1023 atoms e. 8.66 x 1023 atoms 8. Which statements are true? X. The number of electrons determines the identity of the element. Y. The number of neutrons determines which isotope of a given element you have. Z. The number of protons determines the volume (or size) of the atom. a. X and Z b. Y only c. Z only d. Y and Z e. X and Y 9. Remove 20 neutrons, 11 protons, and 13 electrons from 71Ga. What do you have? a. 40Ca b. 48Ar2+ c. 40Ca2+ d. 51Ca e. 51Ca2+ 10. Which of the following statements are false? X. Solid ionic compounds form crystal lattices. Y. In general, molecular compounds have melting points that are higher than those of the ionic compounds. Z. Both molecular and ionic compounds are good conductors of heat. a. X and Y b. Y and Z c. X only d. Z only e. X and YPage 3 of 5 11. Calculate the number of moles of methanol (CH3OH) when given 2.00 L of methanol. The density of methanol is 0.792 g/mL. a. 25.4 mol b. 49.4 mol c. 32.0 mol d. 1.58 mol e. 62.4 mol 12. Name the compound below a. 4-ethyl-3,5,6-trimethylheptane b. 4,5-diethyl-2,3-dimethylhexane c. 2,3-diethyl-4,5-dimethylhexane d. 3-ethyl-1,2-dimethyl-4-(2-methylethyl)pentane e. 4-ethyl-2,3,5-trimethylheptane 13. Which of the following has the greatest force of attraction between them? (Assume the same distance between all pairs). a. Sodium oxide b. Aluminum phosphate c. Magnesium sulfide d. Sodium iodide 14. Given a compound that is 40.0% C, 6.70% H and 53.3% O, with a molar mass of 180.1554 g/mol, find the molecular formula. a. C40H7O53 b. C6H12O6 c. C10H20O10 d. CH2O e. C3H6O3 15. Which element is not in its elemental form? a. Li2(s) b. H2(g) c. P4(s) d. N2(g) e. S8(s)Page 4 of 5 16. Given 5.50 mol of CuSO4(aq) and 5.50 mol of NaOH(aq). How many moles of excess reactant remain? NaOH(aq) + CuSO4(aq) → Cu(OH)2(s) + Na2SO4(aq) a. 2.75 mol excess CuSO4(aq) b. 0.0181 mol excess CuSO4(aq) c. 2.75 mol excess NaOH(aq) d. 0.115 mol excess NaOH(aq) e. The reaction is stoichiometric (i.e., no excess reactant) 17. What is the stoichiometric coefficient for H2S when you balance the following equation? H2O + Al2S3 → H2S + Al(OH)3 a. 1 b. 2 c. 6 d. 3 e. 4 18. Given 192 g of Br2(g) in excess NO(g), if you obtain 183 g of NOBr(g), what is your percent yield? Br2(g) + NO(g) → NOBr(g) a. Greater than 100% b. 68.8% c. 72.1% d. 95.3% e. 69.3% 19. You are given 15.0 g CH4(g) and 115 g of Cl2(g). How many grams of CH2Cl2(g) could you theoretically make? CH4(aq) + Cl2(g) → CH2Cl2(g) + HCl(g) a. 39.7 g b. 68.9 g c. 84.9 g d. 138 g e. 79.4 g Equations & Constants Coulomb’s Law Mass of proton = 1.00728 amu Mass of a neutron = 1.00866 amuPage 5 of 5 20. Fill-in-the-Blank (2 points per blank, no partial credit) ***Write molar masses out to 3 decimal places ***For Type of Compound: Ionic = A, Organic = B, Inorganic/Molecular = C Name Molecular formula Molar mass (g/mol) Type of compound (write the Manganese(II) thiosulfate Hexane NO2 Na2SO3 21. Identify the type of organic compound (2 points per blank, no partial credit) Structural formula Type of organic