L07 Chem 151 Lecture Notes - Lecture 4: Chemical Equation, Covalent Bond, Sodium Hydroxide

EX A. In the below compounds, which phosphorus atom has an oxidation number closest to zero? a. HPO b. H,PO c. HPO, d. H,PO e. H, P2O, EX B. Balanced chemical equations imply which of the following? a. Numbers of molecules are conserved in chemical change b. Numbers of atoms are conserved in chemical change c. Volume is conserved in chemical change. d. Exactl e. None of the above statements are true y two of the above statements are true. EX C. Potassium hydroxide, sodium phosphate, and magnesium bromide all form homogeneous solutions when added to water. Of these three, would be considered strong electrolytes. a. none one c. two d. three EX D. Which of the following reactions does not involve oxidation-reduction? a, CH4 + 3 0, → 2H2O + CO2 b, Zn + 2 HCl → ZnCl, + H, c, 2 Na + 2 H2O → 2 NaOH H, d. MnO, + 4 HCl → Cl2 + 2 H2O + MnCL e. All are oxidation-reduction reactions EX D. Which of the following is not an example of a redox equation? a. 3 H2(g) + Nfg) → 2 NH3(g) b. MgL(aq) + 2 NaOH(aq) → Mg(OH)2(s) + 2 Nal(ag) c. Zn(s) + CuSO4(ag) → ZnSO4(aq) + Cu(s) d. CH4(g) + 2 O2(g) → CO2(g) + 2 H,o@ EX F. Which of the following compounds is soluble in water? a. Ni(OH b. K,PO c. BaSO, d. CoCO e. PbCl

WHICH OF THE FOLLOWING IS NOT AN ARRHENIUS BASE? KOH NH3 LiOH Sr(OH)2 Mg(OH)2 WHICH OF THE FOLLOWING IS A STRONG ACID IN AQUEOUS SOLUTION? HC2H3O2 HC1 HC1O2 H2S HC1O WHICH OF THE FOLLOWING REACTIONS IS NOT AN ACID-BASE REACTION? CaO + SiO2 rightarrow CaSiO3 CH3CHO + H2 rightarrow CH3CH2OH PO4^3- + H2O rightarrow HPO4^2- + OH- Na2O + SO3 rightarrow Na2SO4 BF3 + NH3 rightarrow F3BNH3 ALL OF THE FOLLOWING ARE OXIDATION-REDUCTION REACTIONS EXCEPT: H2(G) + F2 rightarrow 2HF(G) Ca(S) + H2(G) rightarrow CAH2(S) 2K(S) + 2H2O(L) rightarrow 2KOH(AQ) H2(G) 6Li(S) + N2(G) rightarrow 2Li3N(S) Mg3N2(S) + 6H2O(L) rightarrow 3Mg(OH)2(S) + 2NH3(G) WHICH OF THE FOLLOWING IS BEST DESCRIBED AS AN OXIDATION-REDUCTION REACTION? SO2(G) + H20(L) rightarrow H2SO3(AQ) 2C1(G) rightarrow C12(G) 3O2(G) rightarrow 2O3(G) 2NO2(G) rightarrow N2O4(G) SO2(G) + O2(G) rightarrow SO3 WHICH OF THE FOLLOWING REACTIONS INVOLVES NEITHER OXIDATION NOR REDUCTION? N2 + 3H2 rightarrow 2NH3 NH4NO2 rightarrow N2 + 2H2O Cu + 2Ag+ rightarrow Cu^2+ + 2Ag 2CrO4^2- + 2H+ rightarrow Cr2O7^2- + H20 C2H4 + H2 rightarrow C2H6 ASSIGN OXIDATION NUMBERS TO EACH ATOM IN NITROUS ACID. H = +1, N=+5, 0=-l H=+l, N=+5, O=-2 H=+l, N=+3, O=-l H=+l, N=+3, O=0 H=+l, N=+3, O=-2 FOR THE REACTION THAT OCCURS IN A LEAD STORAGE BATTERY, Pb(S) + Pb02(S) + 2H+(AQ) + 2HS04-(AQ) rightarrow 2PbSO4(S) + 2H20(L) THE OXIDIZING AGENT IS HSO4- PbSO4 Pb PbO2 H+ IN THE BALANCED EQUATION 3Na+ + 3OH- + P4 + 2H2O rightarrow 3Na+ + 3H2OP2- + PH3 WHAT IS THE REDUCING AGENT? OH- Na+ H2O P4 PH3 ALL OF THE FOLLOWING REACTIONS ARE CALLED COMBINATION REACTIONS EXCEPT BaO(S) + SO2(G) rightarrow BaSO3(S) C6H10(L) + Br2(L) rightarrow C6H10Br2(L) Br2(L) + H20(L) rightarrow HOBr(AQ) + HBr(AQ) CaC12(S) + 6H2O(L) rightarrow CaC12 * 6H2O(S) 3H2(G) + N2(G) rightarrow 2NH3(G) A 12.0 SAMPLE OF NaOH IS DISSOLVED IN WATER, AND THE SOLUTION IS DILUTED TO GIVE A FINAL VOLUME OF 1.80 L. THE MOLARITY OF THE FINAL SOLUTION IS 6.67 M 0.167 M 0.300 M 0.150 M 1.85 M HOW MANY GRAMS OF LITHIUM NITRATE, LiN03 (68.9 G/MOL), ARE REQUIRED TO PREPARE 511.5 mL OF A 0.101 M LiN03 SOLUTION? 0.000750 G 3.56 G 0.281 G 349 G 0.0735 G WHICH SUBSTANCE WOULD PRODUCE 2 MOL OF PARTICLES PER MOLE OF SOLUTE WHEN DISSOLVED IN WATER? NH4CH3COO CH2O CO2 SO2 A1(NO3)3 WHAT MASS OF H3PO4 (98 G/MOL) IS PRESENT IN 59.7 L OF A 0.0438 M SOLUTION OF H3P)4? 0.0267 G 0.00390 G 2.56 Times 10^2 G 1.34 Times 10^5 G 13.9 G WHICH OF THE FOLLOWING IS A CORRECT STATEMENT OF CHARLE'S LAW, V/T = k THE VOLUME OF A GAS VARIES PROPORTIONALLY WITH THE PRESSURE THE VOLUME OF A GAS SAMPLE VARIES DIRECTLY WITH THE ABSOLUTE TEMPERATURE ALL GAS SAMPLES OF THE SAME VOLUME OF STP CONTAIN THE SAME NUMBER OF ATOMS THE PRESSURE OF A GAS SAMPLE VARIES INVERSELY WITH THE VOLUME. ALL GAS SAMPLES OF THE SAME VOLUME AT STP CONTAIN THE SAME NUMBER OF MOLECULES. THE DENSITY OF A GAS IS 3.48 G/L AT STP. WHAT IS ITS MOLAR MASS? 115.7 G/MOL 104.7 G/MOL 6.4 G/MOL 22.4 G/MOL 78.0 G/MOL WHAT VOLUME OF AMMONIA GAS, MEASURED AT 455.9 MM HG AND 57.4 DEG C, IS REQUIRED TO PRODUCE 2.78 G OF AMMONIUM SULFATE ACCORDING TO THE FOLLOWING BALANCED CHEMICAL EQUATION? 2NH3(G) + H2SO4(AQ) rightarrow (NH4)2SO4(S) 0.0002233 L 0.000931 L 0.476 L 7.38 L 1.90 L CALCIUM NITRATE WILL REACT WITH AMMONIUM CHLORIDE AT SLIGHTLY ELEVATED TEMPERATURES, AS REPRESENTED IN THE EQUATION Ca(NO3)2(S) + 2NH4C1(S) rightarrow 2N2O(G) + CaC12(S) + 4H2O(G) WHAT IS THE MAXIMUM VOLUME OF N20 AT STP THAT COULD BE PRODUCED USING A 2.40-MOL SAMPLE OF EACH REACTANT? 6.55 Times 10^2 L 108 L 1.86 Times 10^-2 L 53.8 L 22.4 L WHAT IS THE PARTIAL PRESSURE OF CARBON DIOXIDE IN A CONTAINER THAT CONTAINS 7.64 MOL OF OXYGEN, 1.68 MOL OF NITROGEN, AND 1.42 MOL OF CARBON DIOXIDE WITH A TOTAL PRESSURE OF 529 MM HP? 376 MMHG 80.6 MMHG 82.7 MMHG 69.9 MMHG 529 MMHG A SAMPLE OF HYDROGEN IS COLLECTED BY WATER DISPLACEMENT AT 23.0 DEG C AND AN ATMOSPHERIC PRESSURE OF 735 MMHG. ITS VOLUME IS 568 ML. AFTER WATER VAPOR IS REMOVED, WHAT VOLUME WOULD THE HYDROGEN OCCUPY AT THE SAME CONDITIONS OF PRESSURE AND TEMPERATRE? (THE VAPOR PRESSURE OF WATER AT 23.0 DEG C IS 21 MMHG)509 mL 539 mL 552 mL 568 mL 585 mL

097 v 0.79 V 1.12 V 1.00 V 1.59 v .77 V 0.27 V NO *NO, al-NO , a NO -> N,0 , NH, 1.25V 0.9 An arrow represents the "properly balanced reduction half-reaction" between the oxidized species on the left and the reduced species on the right of the arrow. The potential value over each arrow is the standard reduction potential And for that properly balanced half-reaction. For example, from this diagram, you can write NO: (a) + + 2 H(ag) NO2g) + HOI): Ented = +0.79 v (R) (18 pts) When HSEis bubbled into nitric acid solutionss(s), NO(R) NOR)Na(R, and NH (ag) all form. (a) (8 pts) write the four balanced reactions that describe this complex process. (b) (8 pts) For each reaction in part (a), calculate the standard emf (in V. (c) (2 pts) Which of the four reactions has the greatest driving force and which has the least driving force per electron? (2) (16 pts) Use the Latimer diagram above for this question. (a) (6 pts) NOgdisproportionates spontaneously into nitric acid and nitrous acid in acidic media. Show this by writing the balanced chemical reaction and evaluating the standard emf for the reaction. (b) (6 pts) Nitrous acid will not disproportionate spontaneously to nitrogen dioxide and nitric oxide, Show this by writing the balanced chemical reaction and evaluating the standard emf for the reaction. (c) (4 pts) Given that the definition of Ivolt - 1 jouleleoul lomb, show that the reduction of the nitrate ion to nitrogen gas in acidic media has a standard reduction potential of +1.25 v. (3) (6 pts) Active metals like zinc will react with concentrated nitric acid to produce the ammonium ion and the Zn (aq) ion at 25°C. (a) (4 pts) write the balanced chemical equation for this process using smallest whole number coefficients. (b) (2 pts) Evaluate AE (V) for the reaction in part (a). (4) (6 pts) Less active metals like copper will react with concentrated nitric acid to produce nitric oxide gas and the Cu *(a) ion at 25°C. (®) (4 pts) write the balanced chemical equation for this process using smallest whole number coefficients. (b) (2 pts) Evaluate AE for the reaction in part (a). BONUS (8 pts, and PRACTICE): Write all balanced half-reactions indicated by the Latimer diagram above.