CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.1 1) d m V 132.1 g 234.4 ml 0.5636 g ml 2) a) 0 ml b) 32.5 ng c) 0.043 km d) 1500 cg 3) a) 65 mi h km (1.6093 ) ( 0 m 1 mi 1 km ) ( 1 h 3600 s ) 29 m s b) 1.00 g ( 1 lb ml ) (0 ) ( 3.7854 L ) 8.35 lb ml 453.59 g 1 L 1 gal gal 4) a) Ba3N2 b) Rb2SO3 c) Pb3(PO4)2 d) Na2S 5) a) magnesium chloride b) barium hydroide c) zinc nitrate d) ammonium acetate e) iron(iii) oide f) copper(ii) sulfate g) dichlorine heptoide h) nitrogen trichloride i) sulfur tetrafluoride 6) a) CaI2 b) KF c) AgClO3 d) CrPO4 e) SrCO3 f) Na2CrO4 g) SF6 h) IBr5 i) P2O10 7) a) sulfuric acid b) hydrochloric acid c) acetic acid 8) a) Al2(SO4)3 + 2H3PO4 2AlPO4 + 3H2SO4 b) P2O5 + 3H2O 2H3PO4 c) 3KBr + Al(NO3)3 3KNO3 + AlBr3 d) 4NH3 + 6NO 5N2 + 6H2O 9) a) synthesis, combustion b) double replacement c) decomposition d) acid-base, double replacement e) single replacement f) combustion 10) a) Al(NO3)3(aq) + LiOH(aq) Al(OH)3(s) + LiNO3(aq) b) Mg(s) + AlCl3(aq) MgCl2(aq) + Al(s) c) K2CO3(aq) + Na3PO4(aq) K3PO4(aq) + Na2CO3(aq) NR d) Ba(ClO3)2(aq) + Na2CO3(aq) BaCO3(s) + NaClO3(aq) e) HNO3(aq) + RbOH(aq) H2O(l) + RbNO3(aq) f) KCl(s) K(s) + Cl2(g) g) Rb(s) + H2O(l) RbOH(aq) + H2(g) h) CaCO3(s) + H3PO4(aq) Ca3(PO4)2(s) + H2O(l) + CO2(g) i) Mg(OH)2(s) MgO(s) + H2O(l)
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.2 11) a) 12(12.01 g) + 22(1.01 g) + 11(16.00 g) 342.34 g C12H22O11 b) 3(207.2 g) + 2(10.81 g) + 6(16.00 g) 739.22 g Pb3(BO3)2 c) 137.33 g + (2(16.00 g) + 2(1.01 g) + 8(18.02 g) 315.51 g Ba(OH)2 8H2O 12) a) 3.015 mol MgCl 2 ( 95.21 g MgCl 2 1 mol MgCl 2 ) 287.1 g MgCl 2 b) 3.2 10 22 1 mol CO 2 CO 2 molecules ( 6.022 10 23 CO 2 molecules ) (44.01 g CO 2 ) 2.3 g CO 1 mol CO 2 2 13) a) 15.3 g C 4 H 10 ( 1 mol C 4H 10 58.14 g C 4 H 10 ) 0.263 mol C 4 H 10 b) 5.803 10 24 1 mol N 2 O 3 N 2 O 3 molecules ( 6.022 10 23 N 2 O 3 molecules ) 9.636 mol N 2O 3 14) a) 3.00 mol O 2 ( 6.022 1023 O 2 molecules 1 mol O 2 ) ( 2 O atoms 1 O 2 molecule ) 3.61 1024 O atoms b) 44.93 g Al 2 (CrO 4 ) 3 ( 1 mol Al 2(CrO 4 ) 3 6.022 10 23 Al 2 (CrO 4 ) ) ( 3 12 O atoms ) ( ) 8.077 10 23 O atoms 401.96 g Al 2 (CrO 4 ) 3 1 mol Al 2 (CrO 4 ) 3 1 Al 2 (CrO 4 ) 3 15) a) M mol solute L solution 0.825 mol 1.5000 L 0.550 M NaCl b) M g solute (MM solute)(l solution) 15.00 g (58.44 g 0.114 M NaCl )(2.25 L) mol 16) % solute mass solute mass solute + mass solvent 30.0 g NaOH 30.0 g NaOH + 125.0 g H 2 O 30.0 g NaOH 155.0 g solution 155.0 300 0 g 19.4 % NaOH
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.3 17) M g solute (MM solute)(l solution) 3.00 M g solute (40.00 g )(0.2500 L) mol g solute 30.0 g NaOH 18) Na2Cr2O7 261.98 g/mol % element molar mass element molar mass compound Na: 2(22.99 g) 261.98 g Cr: 2(52.00 g) 261.98 g O: (17.55 + 39.70) 42.75% O 261.98 4598 261.98 10400 17.55% Na 39.70% Cr 19) mass % solute mass solute mass solute + mass solvent 20.0 50.0 g 50.0 g + 0 + 20.0 5000 20.0 4000 200. g H2O 200. ml H2O (1 g H2O 1 ml H2O since density of water 1.00 g ml ) 20) a) assume g total sample, therefore starting with 63.5 g Ag, 8.2 g N, and 28.2 g O 1 mol Al 63.5 g Ag ( ) 0.589 mol Ag 107.87 g Ag 8.2 g N ( 1 mol N ) 0.59 mol N 14.01 g N Ag 0.589 N 0.59 O 1.76 0.589 0.589 0.589 Ag1.00N1.00O2.99 AgNO3 28.2 g O ( 1 mol O ) 1.76 mol O 16.00 g O b) 26.6 g K ( 1 mol K ) 0.680 mol K 39.10 g K 1 mol Cr 35.4 g Cr ( ) 0.681 mol Cr 52.00 g Cr 38.0 g O ( 1 mol O ) 2.38 mol O 16.00 g O K 0.680 N 0.681 O 2.38 0.680 0.680 0.680 K1.00Cr1.00O3.50 K2Cr2O7
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.4 21) assume g total sample, therefore starting with 54.6 g C, 9.0 g H, and 36.4 g O 54.6 g C ( 1 mol C ) 4.55 mol C 12.01 g C 9.0 g H ( 1 mol H ) 8.9 mol H 1.01 g H C 4.55 H 8.9 O 2.28 2.28 2.28 2.28 C2.00H3.9O1.00 C2H4O empirical formula 36.4 g O ( 1 mol O ) 2.28 mol O 16.00 g O molar mass C2H4O 44.06 g 176 g 44.06 g 3.99 4 molecular formula: C8H16O4 22) 2Al + Fe2O3 Al2O3 + 2Fe a) 27.8 g Fe 2 O 3 ( 1 mol Fe 2O 3 2 mol Al ) ( ) 0.348 mol Al 159.70 g Fe 2 O 3 1 mol Fe 2 O 3 1 mol Al b) 20.0 g Al ( 26.98 g Al ) (1 mol Al 2O 3 ) ( 101.96 g Al 2O 3 ) 37.8 g Al 2 mol Al 1 mol Al 2 O 2 O 3 3 23) 3Ca(ClO3)2(aq) + 2Na3PO4(aq) Ca3(PO4)2(s) + 6NaClO3(aq) a) 25.00 g Ca(ClO 3 ) 2 ( 1 mol Ca(ClO 3) 2 206.98 g Ca(ClO 3 ) 2 ) ( 1 mol Ca 3(PO 4 ) 2 3 mol Ca(ClO 3 ) 2 ) ( 310.18 g Ca 3(PO 4 ) 2 1 mol Ca 3 (PO 4 ) 2 ) 12.49 g Ca 3 (PO 4 ) 2 40.00 g Na 3 PO 4 ( 1 mol Na 3PO 4 163.94 g Na 3 PO 4 ) ( 1 mol Ca 3(PO 4 ) 2 2 mol Na 3 PO 4 ) ( 310.18 g Ca 3(PO 4 ) 2 1 mol Ca 3 (PO 4 ) 2 ) 37.84 g Ca 3 (PO 4 ) 2 b) Ca(ClO3)2 c) 25.00 g Ca(ClO 3 ) 2 ( 1 mol Ca(ClO 3) 2 206.98 g Ca(ClO 3 ) 2 ) ( 2 mol Na 3PO 4 3 mol Ca(ClO 3 ) 2 ) ( 163.94 g Na 3PO 4 1 mol Na 3 PO 4 ) 13.20 g Na 3 PO 4 reacted 40.00 g 13.20 g 26.80 g Na3PO4 in ecess
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.5 24) 2H3PO4 + 3Na2CO3 2Na3PO4 + 3CO2 + 3H2O a) 25.00 ml H 3 PO 4 ( 0.750 mol H 3PO 4 0 ml H 3 PO 4 ) ( 3 mol Na 2CO 3 2 mol H 3 PO 4 ) ( 105.99 g Na 2CO 3 1 mol Na 2 CO 3 ) 2.98 g Na 2 CO 3 b) 75.0 ml H 3 PO 4 ( 1.10 mol H 3PO 4 0 ml H 3 PO 4 ) ( 3 mol CO 2 2 mol H 3 PO 4 ) ( 44.01 g CO 2 1 mol CO 2 ) 5.45 g CO 2.0 ml Na 2 CO 3 ( 0.950 mol Na 2CO 3 0 ml Na 2 CO 3 ) ( 3 mol CO 2 3 mol Na 2 CO 3 ) ( 44.01 g CO 2 1 mol CO 2 ) 4.18 g CO 2 c) Na2CO3 25) 2C8H18(l) + 25O2(g) 16CO2(g) + 18H2O(l) a) 30.25 L O 2 ( 16 mol CO 2 25 mol O 2 ) 19.36 L O 2 b).0 g C 8 H 18 ( 1 mol C 8H 18 114.26 g C 8 H 18 ) ( 25 mol O 2 2 mol C 8 H 18 ) ( 22.4 L O 2 1 mol O 2 ) 245 L O 2 c) T 23.0 C 296.2 K P 1.055 atm need new molar V: PV nrt V nrt P L atm (1 mol)(0.08206 mol K )(296.2 K) 1.055 atm 23.04 L 14.8 L O 2 ( 1 mol O 2 23.04 L O 2 ) ( 18 mol H 2O 25 mol O 2 ) ( 18.02 g H 2O 1 mol H 2 O ) 8.33 g H 2O 26) a) 3Ca(ClO3)2(aq) + 2Na3PO4(aq) Ca3(PO4)2(s) + 6NaClO3(aq) ionic 3Ca 2+ (aq) + 6ClO3 (aq)+ 6Na + (aq) + 2PO4 3 (aq) Ca3(PO4)2(s) + 6Na + (aq) + 6ClO3 (aq) net 3Ca 2+ (aq) + 2PO4 3 (aq) Ca3(PO4)2(s) b) 8KClO3(aq) + C12H22O11(s) 8KCl(aq) + 12CO2(g) + 11H2O(l) ionic 8K + (aq) + 8ClO3 (aq) + C12H22O11(s) 8K + (aq) + 8Cl (aq) + 12CO2(g) + 11H2O(l) net 8ClO3 (aq) + C12H22O11(s) 8Cl (aq) + 12CO2(g) + 11H2O(l) c) Zn(s) + 2AgNO3(aq) Zn(NO3)2(aq) + 2Ag(s) ionic Zn(s) + 2Ag + (aq) + 2NO3 (aq) Zn 2+ (aq) + 2 NO3 (aq) + 2Ag(s) net Zn(s) + 2Ag + (aq) Zn 2+ (aq) + 2Ag(s) 27) a) beta decay b) positron decay c) electron capture d) fission e) fusion
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.6 121 28) a) 51Sb 0 1 e 121 + 50Sn c) 17Cl 35 35 + -1 0 e 16S 0 + 0 γ 222 b) 86Rn 4 2He 218 + 84Po d) 235 U 92 235 93-1 0 e + Np 104 29) a) Ag 47-1 0 104 e + 48Cd c) 238 92U 12 + 6 C 246 98Cf 1 + 4 0 n 220 b) 86Rn 216 84Po 4 + 2He d) 235 U 92 1 + 0 n 139 56Ba 94 + 36Kr 1 +3 0 n 30) 2 ways to do this one: in 2 hrs there are 8 15 min segments, so there are 8 half-lives original mass ( 1 2 ) # half-lifes final mass 300 g ( 1 2 ) 8 1.172 g count and divide by 2: # half-lifes mass left 0 300 g 1 150 g 2 75 g 3 37.5 4 18.75 g 5 9.375 g 6 4.688 g 7 2.344 g 8 1.172 g 31) To find the number of half-lifes, the factor between the original and final decay rates is a power of 2 of the number of half-lifes. 13.6 decay/min/g 0.2125 decay/min/g 64 2 64 6 half-lifes (5730 yrs)(6) 34380 yrs 32) V1 50.0 ml T1 28 C 301 K T2 93 C 366 K V2? V 1 T 1 V 2 T 2 V 2 V 1T 2 (50.0 ml)(366 K) T 1 301 K 60.8 ml 33) V1 2325 ml P1 775 torr T1 20.3 C 293.4 K V2? P2 760 torr T2 273.15 K P 1 V 1 T 1 P 2V 2 T 2 P1V1T2 P2V2T1 V 2 P 1V 1 T 2 P 2 T 1 (775 torr)(2325 ml)(273.15 K) (760 torr)(293.4 K) 2210 ml
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.7 34) P1 89.2 kpa T1 26.0 C 299.2 K T2 95.0 C 368.2 K P2? P 1 T 1 P 2 T 2 P 2 P 1T 2 T 1 (89.2 kpa)(368.2 K) 299.2 K 110. kpa 35) note: 1 cm 3 1 ml V1 435 cm 3 P1 755.2 torr P2 843.1 torr V2? P1V1 P2V2 V 2 P 1V 1 (755.2 torr)(435 cm3 ) P 2 843.1 torr 390. cm 3 36) rate NH 3 rate N 2 H 4 MM N 2 H 4 MM NH3 32.06 g 17.04 g 1.372 NH3 is 1.372 times faster than N2H4. 37) rate NH3 50.00 ml/min rate unk 28.76 ml/min MM unk? rate NH 3 rate unk MM unk MM NH3 rate unk rate NH 3 MM NH 3 MM unk 50.00 ml/min 28.76 ml/min 17.04 g 28.76 ml/min 50.00 ml/min 17.04 g 1.739 17.04 g 2 1.739 2 ( 17.04 g ) 3.024 51.53 g 17.04 g OR 0.5752 17.04 g 2 0.5752 2 ( 17.04 g ) 0.3309 17.04 g 0.3309 17.04 g 51.50 g 38) V1 20.0 L n1 0.956 mol V2 30.0 L n2? V 1 n 1 V 2 n 2 V 1 n 2 V 2 n 1 n 2 V 2n 1 V 1 (30.0 L)(0.956 mol) 20.0 L 1.43 mol
CHEMISTRY WKST KEY: SEMESTER 1 REVIEW PROBLEMS p.8 39) NUCLEAR SYMBOL 27 ATOMIC MASS OF p + OF n OF e CHARGE 13Al 13 27 13 14 13 0 64 2+ 29Cu 29 64 29 35 27 2+ 80 1 35Br 35 80 35 45 36 1-201 2+ 80 201 80 121 78 2+ 80 Hg 75 3 33As 33 75 33 42 36 3-32 2 16 32 16 16 18 2-16S 39 19K 19 39 19 20 19 0 40) V? g.0 g O2 1 atm P 90.00 kpa ( ) 0.8882 atm 101.325 kpa T 52.2 C 325.4 K PV grt MM V grt P(MM) L atm (.0 g)(0.08206 )(325.4 K) mol K (0.8882 atm)(32.00 g mol ) 93.95 L