CHM 130 Exam 2 – Chapters 12, 6, 7, 16, and 8

Name: ____KEY_________________ CHM 130 Exam 2 – Chapters 12, 6, 7, 16, and 8 Show all work and clearly mark final answers to receive full credit. 18. (5 pts) Predict which of the following has an ionic bond. Circle all that apply. a. CO2 c. SO3 d. MgCl2 e. OF2 b. SnO2 19. (4 pts) For the following atoms, identify whether each bond is polar and the direction of polarity using delta notation ( + and -) and dipole arrows (⟻ , ⟼). If nonpolar, leave it blank. a. Br – Br b. C – H + ⟼ c. N – F + ⟼ d. C – Cl 20. (8 pts) a. Draw the electron dot structure for phosphorus triiodide, PI3 in the space below. Three single bonds; one lone e- pair on P b. What is the ABE notation for this molecule? __AB3E__________ c. What is its molecular geometry (or shape)? __trigonal pyramidal_________ d. What are the bond angles in this molecule? ___< 109.5o________ e. What type(s) of bonds are in the molecule (ionic, polar covalent, nonpolar covalent? __PC_______ f. Is the molecule polar or nonpolar? ___polar______________ 1. (4 pts) Label the following as ionic compound, covalent compound (or molecule), or acid. a. P2O5 __covalent_________ b. MgF2 __ionic compound_____ c. H3PO4(aq) ___acid___________ d. KNO3 __ionic compound____ 2. (12points) Write the correct names for the given formulas and correct formulas for the given names. Formulas Names Fe2(SO4)3 iron (III) sulfate Cl2O5 dichlorine pentoxide ZnCO3 zinc carbonate page 1 of 3 Name: ____KEY_________________ S2Cl2 disulfur dichloride HNO3(aq) nitric acid CuI2 copper (II) iodide 3. (7 pts) List the 7 diatomic elements (by formula): __H2, N2, F2, O2, I2, Cl2, Br2______ 4. (9 pts) Identify the type of reaction for each equation below. Also balance each equation. Your options for types of reactions are: combination (C), decomposition (D), combustion (B), single replacement (SR), double replacement (DR), or acid base neutralization (N). a. Type: __SR____ _3__ Ba (s) + _2__ H3PO4 (aq)  _3__ H2 (g) + ____ Ba3(PO4)2 (s) b. Type: __C_______ _2__ K (s) + ____ F2 (g)  _2___ KF (s) c. Type: __DR_______ ____ Na2SO4 (aq) + ____ BaCl2 (aq)  ____ BaSO4 (s) + _2__ NaCl (aq) 5. (6 pts) Determine whether each compound will be soluble or insoluble in water by including their physical states on the line after each one. Then draw what happens to each one when it is placed in water. a. (NH4)2S _(aq)_ b. AgI _(s)_ 6. (2 pts) Will Ag(s) react with PbCl2? Circle: Yes No 7. (2 pts) Will Zn(s) react with CoCl3? Circle: Yes No c. NaNO3 _(aq)_ 8. (10 pts) Predict products (including physical states – s, l, g, or aq) for the following reactants. If no reaction occurs, write NR. You do not need to indicate what type of reaction each one is. a. ___ Cu(NO3)2 (aq) + ___ (NH4)2S (aq)  ___CuS (s) + 2 NH4NO3 (aq)_______ b. _2_ NaOH (aq) + ___ H2SO4 (aq)  ___Na2SO4 (aq) + 2 H2O(l)_____ c. ___ C4H8 (l) + _6__ O2 (g)  ___4 CO2 (g) + 4 H2O (g)_______ d. ___ K (s) + ____ NaNO3 (aq)  __Na (s) + KNO3 (aq)___________________ page 2 of 3 Name: ____KEY_________________ _B__ 9. (3 pts) Consider the reaction Al (s) + O2 (g)  Al2O3 (s). What is reduced? a. Al (s) b. O2 (g) c. Al2O3 (s) d. nothing _B__ 10. (3 pts) Consider the reaction Al (s) + O2 (g)  Al2O3 (s). What is the oxidizing agent? a. Al (s) b. O2 (g) c. Al2O3 (s) d. nothing 11. (4 pts) Briefly describe what a catalyst does in a chemical reaction. Also briefly describe HOW does it does this. A catalyst speeds up a reaction. It does this by lowering the activation energy for a reaction by providing an alternate reaction pathway. 12. (2 pts) True or system. False: An endothermic reaction is one in which energy is absorbed by the 13. (3 pts) If you wanted to prepare a sample that had 1 mole of neon gas, a. What mass would this sample weigh? ___20.18 g____ b. How many atoms would be in this sample? ___6.02 x 1023 atoms____ c. At STP, how big would the container to hold the gas need to be (i.e., what volume, in L, would it occupy)? _____22.4 L______ 14. (4 pts) How many molecules are in 0.105 mol of NH3? 0.105 mol NH3 x (6.02 x 1023 molecules / 1 mol) = 6.32 x 1022 molecules NH3 15. (4 pts) Calculate the molar mass of magnesium phosphate, Mg3(PO4)2 (with correct units). Mg: 3 x 24.31; P: 2 x 30.97; O: 8 x 16.00; total = 262.87 g/mol page 3 of 3