CHEMISTRY 207 SAMPLE TEST QUESTIONS 1. Circle the correct answer. a. Which one of the following does not have resonance structures? b, Which one of the following has a square pyramid shape? c. Which one of the following molecules has a net dipole moment. The shape of the molecule is given below in parentheses. CF4 CH4 SO2 BH3 (tetrahedral) (tetrahedral) (bent) (trigonal planar) d. Which of the following is probably NOT a stable compound PH3 MgO MgF3 e. Which of the following molecules has the biggest dipole moment? H2 HF BrCl Li2O IBr f. Which one of the following molecules does NOT have a net dipole moment. The shape of the molecule is given below in parentheses. SF4 BF2Br CO2 NF3 (see-saw) (trigonal planar) linear (trigonal pyramid) g. Which one of the following has sp3 hybridization on the central atom? h. Which of the following ions is most likely to be stable. (Hint: consider the Lewis structures) NH NH2 NH3 NH4 i. Which of the following molecules has a Lewis structure similar to that of N2? CO H2 O2 Cl2 j. What is the formal charge on the sulfur atom in the figure on the right? +1 -1 0 -2 k. Which of the following bonds is least polar? HF ClBr CF 1 OF CHEMISTRY 207 SAMPLE TEST QUESTIONS l. Including the one shown on the right, how many resonance forms can be drawn for PO43- O O P O O 2 m. 3 5 2 4 Which one of the following is linear? n. How many orbitals are there a set sp hybrid orbitals? 0 1 o. 4 Which of the following molecules has a net dipole moment BF3 FCCF CCl4 trigonal planar linear tetrahedral ICl3 T shaped p. Select the molecule in which the central atom violates the octet rule BF3 NH3 CO2 PH3 q. Which of the following is a planar molecule CH4 BH3 PCl5 NH3 r. A molecule with sp3d hybridization on the central atom always has a trigonal bipyramid geometry always has five pairs of electrons or bonded atoms around the central atom always has five bonds on the central atom always is a non planar molecule s. The angle between the H-N-H bonds in NH3 is closest to 90 o 109.5 o 120 o 180 o t. Which of the following is the balanced net ionic equation for the precipitation of calcium phosphate when aqueous solutions of sodium phosphate and calcium chloride are mixed . 2Na3PO4(aq) + 3 CaCl2(aq) 6 NaCl(aq) + Ca3(PO4)2(s) 2 PO4(aq) + 3 Ca(aq) Ca3(PO4)2(s) PO4(aq) + Ca(aq) CaPO4(s) 6 Na(aq) + 2PO4(aq) + 3Ca(aq) +6 Cl(aq) 6 Na(aq) + 6 Cl(aq) + Ca3(PO4)2(s) u. Which one of the following is an acid base reaction? 2 HCl + Mg H2 + MgCl2 HCl + KOH H2O + KCl C(s) + O2(g) CO2(g) S8(s) + 4 Cl2 (g) 4 S2Cl2(l) v. Which of the following salts is insoluble in water? FeCl3 Na2CO3 2 Pb(NO3)2 Mn3(PO4)2 CHEMISTRY 207 SAMPLE TEST QUESTIONS w. In which of the following molecules does Mn have an oxidation number of +6. MnS KMnO4 K2MnO4 MnO2 x. Which of the following reactions is NOT a redox reaction? Cu(s) + F2(g) CuF2(s) K2SO4(aq) + BaCl2(aq) BaSO4(s) + 2KCl(aq) 2HCl + Mg(s) H2(g) + MgCl2(aq) C(s) + O2(g) CO2(g) y. Which of the following is a fusion reaction? 7 4 Be 73 Li 0 1 He 11H 42 He 01 4 Rn 218 84 Po 2 He 3 2 222 86 n 1 0 235 92 U Te 137 52 97 40 Zr 201 n z. The reactions in nuclear reactors can be best characterized as Fusion Fission Alpha decay aa. In the reaction alpha particle 27 13 Al ? Gamma decay Na 42 He , the missing particle must be a(an) 24 11 beta particle neutron positron bb. 232Th undergoes alpha decay. The decay product undergoes a beta decay. What is the product of the second decay? 228 228 232 228 Rn Ac Ac Th cc Which of the following types of materials is most dangerous if ingested Alpha emitters Beta emitters Gamma emitters x-ray emitters dd What is the missing product for the fission reaction shown below 236 142 91 + + ? 56 Ba 92 U 36 Kr three protons three neutrons An alpha particle A beta particle ee. The half-life for decay of 3H is 11 yr. How many years must pass to reduce a 16.0 gram sample to 2.0 g. 11 yrs 22 yrs 33 yrs 44 yrs ff. If an isotope is above the belt of stability in the plot of number of neutrons vs. number of protons then the isotope will most likely decay by electron capture beta emission positron emission alpha emission gg. Which one of the following is a ( antibonding) orbital? 3 CHEMISTRY 207 hh. SAMPLE TEST QUESTIONS Which one of the following statements is TRUE? Bond length tends to decrease as bond strength increases Bond length tends to increase as bond strength increases Single bonds tend to be shorter than double bonds Triple bonds tend to be longer than double bonds ________________________________________________________________ A B C D a. Which of the diagrams above corresponds to a molecule with a triple bond? ______ b Which of the diagrams above corresponds molecule with no net bonds? ________ c. Which of the diagrams above could correspond to a N2 molecule? ________ d Which of the diagrams above corresponds to a paramagnetic molecule? ________ e. Which of the diagrams above corresponds to a molecule with a double bond? ______ f. Which of the diagrams above corresponds to a molecule with a single bond? ______ ______________________________________________________________________________ _____ 2. Fill in the blank a. How many grams of Na are in 10g of NaOH? ______________ b. How many moles of NaCl are in 100 mL of 2 M NaCl____________ c. The molecule HCN contains __ bonds and __ bonds. d. How many moles of hydrogen atoms are in ten moles of Ca(OH)2 _______________ e. How many S atoms are in two moles of S2Cl2 _________________ f. Give the approximate values of the angles shown in the figure on the right ____, _____ h. 10 mL of a 2.5 M NaCl solution contains __________ moles of NaCl 4 CHEMISTRY 207 i. SAMPLE TEST QUESTIONS For CrO4 the oxidation numbers are ___ for Cr and _____ for O What is the missing isotope in the following reaction ______________ 236 141 + ? + 3 01n 92 U 56 Ba Balance the following equations C6H14(l) + O2(g) CO2(g) + H2O(l) CH3NH2 (l) + O2(g) CO2(g) + H2O(l) + N2(g) _______________________________________________________________________________ Consider the reaction S8(s) + 4 Cl2 (g) 4 S2Cl2(l) If 10.00 g of S8 reacts as completely as possible with 8.00 g of Cl2, how many grams of S2Cl2(l) will be formed. Show all calculations and report the answer to the correct number of significant figures. _______________________________________________________________________________ A compound 69.58% Ba, 6.090% C and 24.32% O. What is its empirical formula? _______________________________________________________________________________ How many grams of C are in 50.0 g. of Na2CO3 What is the molarity of Na2CO3 solution that is made by dissolving 2.0 g of Na2CO3 in 250.00 mL of water. _______________________________________________________________________________ What is the molarity of the solution made by diluting 25.0 mL of 2.0 M hydrochloric acid to a final volume of 1.500 L. _______________________________________________________________________________ Write balanced net ionic equations for the following reactions. K2CO3(aq) and CuCl2(aq) BaCl2(aq) + AgNO3(aq) Write a balanced nuclear equation for each of the following 5 CHEMISTRY 207 SAMPLE TEST QUESTIONS positron emission by 11C alpha decay of 218Pb Draw Lewis structures for the following compounds. Show formal charges and resonance structures if appropriate. CH3F ClO3 HCN ELECTRONEGATIVITIES H Li Na K Rb Cs 2.1 1.0 0.9 0.8 0.8 0.7 Be Mg Ca Sr Ba 1.5 1.2 1.0 0.9 0.9 B Al Ga In Tl 2.0 1.5 1.8 1.7 1.8 C Si Ge Sn Pb 2.5 1.8 1.8 1.8 1.9 N P As Sb Bi 6 3.0 2.1 2.0 1.9 1.9 O S Se Te Po 3.5 2.5 2.4 2.1 2.0 F Cl Br I At 4.0 3.0 2.8 2.5 2.2