CH1410 Practice Exam #2 (Katz) Sp2015

Transcription

1 H1410 Practice Eam #2 (Katz) Sp2015 Section 1 - Multiple hoice - Write the letter of the EST HOIE in the space provided. 1. The energy sublevel for the highest energy electrons added to the elements U, Sr, l, and u are, in the correct order, A A) s, p, d, f ) f,s,p,d. ) p, d,f, s. ) f,p,d,s. 2. Which subshell letter corresponds to a spherical orbital? A) s ) p ) d ) f 3. What is the electron configuration for Kr? A) 1s22s22p63s23p43d104s24p6 ) 1s22s22p63s23p64s23d24p6 ) 1s22s22p63s23p64s23d104p6 ) 1s22s22p63s23p24s23d104p6 4. onsider the electron configuration of the ion to determine which ion shown below has an incorrect ionic charge? A) Al3+ ) Se2+ ) Rb+ ) a2+ 5. Which one of the following species has the electron configuration of 1s22s 2 2p 6? 1. Na+ 2. O2-3. F- A) 1 and 2 only ) 1 and 3 only ) 2 and 3 only ) 1, 2, and 3 6. Which of the following atoms is the largest? A A) Na ) K ) Rb ) s 7. Which of the following atoms has the greatest metallic character? A) s ) e ) u ) Ti 8. How many carbon atoms are in the formula unit Al2(O3)3? A) 9 ) 6 ) 3 ) 1

2 9. How many of each type of atom are there in the formula (NH4)2HPO4? A) N = 2, H = 9, P = 1, O = 4 ) N = 1, H = 5, P = 1, O = 4 ) N = 2, H = 5, P = 1, O = 4 ) N = 2, H = 8, P = 1, O = Which among the following elements does NOT eist as a diatomic molecule in nature? A) hydrogen ) nitrogen ) fluorine ) neon 11. Which of the following is a molecular compound? A) barium sulfide ) calcium acetate ) potassium hydroide ) nitrogen monoide A 12. What is the name of os? A) cobalt(ii) sulfide ) cobalt sulfide ) cobalt monosulfide ) cobaltous sulfur 13. What is the name of a(no3)2? A) calcium dinitrite ) calcium nitrate ) calcium nitride ) calcium nitrite 14. What is the correct formula for potassium dichromate? A) K(rO4)2 ) Kr2O7 ) K2rO4 ) K2r2O7 A 15. The charge of a vanadium ion in the compound V2O5 is: A) 5+ ) 2+ ) 10+ ) What is the name of the molecular compound SO3? A) sulfur oide ) sulfur(iv) oide ) sulfur trioide ) sulfur tetraoide 17. What is the proper name for Hr (aq)? A) hydrobromous acid ) hydrousbromic acid ) hydrobromic acid ) bromous acid) an isotope. 18. What is the formula mass for potassium nitrate? A) amu ) amu ) amu ) amu

3 19. A compound has a formula mass of amu and is comprised of atoms of sodium and oygen in a definite ratio. The name of the compound described here is A) sodium monoide. ) disodium oide. ) sodium oide. ) sodium dioide. 20. A chromium oide compound contains grams of chromium and 48.0 grams of oygen. What is the most likely empirical formula of this compound? A) ro ) ro2 ) ro3 ) r2o3 21. What is the molecular formula of a compound given the molar mass of the compound is gram and the empirical formula is NH? A) NH ) N2H2 ) N2H6 ) N4H4 22. If you have atoms of copper, how many moles of copper do you have? A) ) 3.00 ) ) How many atoms of lithium are in 11.8 g of Li? A) ) ) ) How many moles of oygen are in 3.70 moles of NalO 4? A) 3.70 ) ) 21.5 ) 14.8

4 25. What is the mass percent of Mg in magnesium chloride (Mgl2)? A) 12.3 ) 40.7 ) 25.6 ) When the equation, O2 + 5H12 O2 + H2O is balanced, the coefficient: of O2 is: A) 3 ) 4 ) 5 ) What are the coefficients for the following reaction when it is properly balanced? Na3PO4 + a(no3)2 NaNO3 + a3(po4)2 A) 2, 1, 1, 3 ) 2, 3, 1, 6 ) 2, 3, 6, 1 ) 6, 1, 3, What are the coefficients for the following reaction when it is properly balanced? nitrogen monoide (g) + carbon monoide (g) nitrogen (g) + carbon dioide (g) A) 2, 1, 1, 2 ) 2, 2, 1, 2 ) 2, 2, 2, 1 ) 1, 1, 2, Sodium metal reacts with water to form aqueous sodium hydroide and hydrogen gas. Which equation below best describes this reaction? A) Na + H2O NaOH (aq) + H (g) ) S + H2O SOH (aq) + H (g) ) Na + H2O NaOH (aq) + H2 (g) ) 2Na + 2H2O 2NaOH (aq) + H2 (g)

5 HAPTER 8 QUESTIONS: 30. How many moles of H2 can be made from complete reaction of 3.0 moles of Al? Given: 2 Al + 6 Hl 2 All3 + 3 H2 A) 3 moles ) 3.0 moles ) 4.5 moles ) 9.0 moles 31. How many moles of sodium metal are needed to make 3.6 moles of sodium chloride? Given the reaction: 2Na + l2 2Nal A) 0.9 ) 7.2 ) 1.8 ) Given the balanced equation O2 + Si SiO2 +, if you were to react 1 mole of O2 with 1 mole of Si, which statement is TRUE? A) The O2 is the limiting reactant. ) The Si is the limiting reactant. ) The SiO2 is the limiting reactant. ) You have equal stoichiometric amounts of reactants. 33. The theoretical yield of a reaction is 75.0 grams of product and the actual yield is 42.0g. What is the percent yield? A) 75.0 ) 56.0 ) 31.5 ) onsider the following reaction: 2 Mg + O2 2 MgO H rn = kj alculate the amount of heat (in kj) associated with complete reaction of 4 moles of Mg. A) kj ) kj ) kj ) kj

6 Section 2 - Answer the following computational questions using the information provided. You must show a plan for your calculations, along with the conversion factors involved for full credit. Write your answer in the bo provided. 1. How many atoms of potassium are contained in 3.00 mol of K3PO4? (Avogadro s number = ) 3.00 mol K3PO4 Plan and alculations: 3.00 mol K 1.00 mol K3PO K atoms 1.00 mol K = K atoms 2. How many moles of calcium phosphate are in g of a 3 (PO 4 ) 2? (atomic weights: a, 40.08; P, 30.97; O, 16.00) Molar Mass alculation: 3(40.08) + 2(30.97) + 8(16.00) = Plan and alculations: g a3(po4) mol a3(po4) g a3(po4)2 = mol a3(po4)2

7 3. How many moles of carbon are contained in g of Pb(O 3 ) 2? (atomic weights: Pb, ;, 12.01; O, 16.00) Molar Mass alculation: (12.01) + 6(16.00) = Plan and alculations: g Pb(O3) mol Pb(O3) mol g Pb(O3) mol Pb(O3)2 4. How many grams of sodium are contained in g of NaHO 3 (molar mass = 84.01)? = mol Plan and alculations: g NaHO mol NaHO g NaHO mol Na 1.00 mol NaHO g Na mol = g mol Na g Na or g NaHO3

8 5. How many moles of NH3 can theoretically be produced by the reaction of 2.00 g of N2 with 3.00 g H2? (Molar masses: N2, 28.02; H2, 2.02) Reaction: N2(g) + 3 H2(g) 2 NH3(g) 2.00 g N mol N g N g H mol H g H2 6. In the following reaction, if you start with 42.0 g of O2 and 99.9 g KOH, which is the limiting reactant? (Molar masses: O2, 44.01; KOH, 56.11) Reaction: O2 + 2KOH K2O3 + H2O 42.0 g O mol O g O g KOH 1.00 mol KOH g KOH 2.00 mol NH mol N mol NH mol H mol K2O3 (or H2O) 1.00 mol 7. If you start with 15.5 g of Na2S and 12.1 g uso4 and produce only 3.05 g of us, what is the percent yield of us for the following reaction? (Molar masses: Na2S, 78.05; us, 95.62; uso4, ) 15.5 g Na2S 1.00 mol Na2S g Na2S 1.00 mol K2O3 (or H2O) 2.00 mol KOH Reaction: Na2S + uso4 Na2SO4 + us 1.00 mol us 1.00 mol Na2S = mol NH3 = mol NH3 = mol = mol g us g Na mol us 12.1 g 1.00 mol uso4 uso g uso4 (3.05/7.34) 100 = 41.6% 1.00 mol us 1.00 mol uso4 = g us g us g Na mol us = g us