In the half reaction I 2 2 I the iodine is (a) reduced (b) oxidized (c) neither of the above

Transcription

1 In the half reactin I 2 2 I the idine is (a) reduced (b) xidized (c) neither f the abve

2 Vitamin C is an "antixidant". This is because it (a) xidizes readily (b) is an xidizing agent (c) neither f the abve

3 In which f the fllwing is the xidatin number f idine greatest? (a) I 2 (b) IO (c) IO 2 (d) IO 2

4 If a reducing agent is t be used t generate the varius xidatin states f vanadium, ne shuld start with (a) VO 3 (yellw) (b) VO 2+ (green) (c) V 3+ (blue) (d) V 2+ (vilet)

5 In the reactin 2 H 2 O 2 2 H 2 O + O 2 xygen is (a) xidized (b) reduced (c) neither xidized r reduced (d) bth xidized and reduced

6 When tw f the fllwing cmpunds are mixed, a redx reactin ccurs in which the third is frmed. Which is the prduct? (a) SO 2 (b) S (c) H 2 S

7 Prtein flding is ften stabilized by the frmatin f disulfide bnds between cysteine side chains. In this reactin SH HS S S the sulfur is (a) reduced (b) xidized (c) neither f the abve

8 In balancing the xidatin f methanl t frmic acid CH 3 OH HCOOH (skeletal) the number f electrns that must be added t the right side is (a) 0 (b) 2 (c) 4 (d) 6

9 In balancing the half-reactin CN CNO (skeletal) the number f electrns that must be added is (a) 0 (b) 2 n the left (c) 2 n the right

10 In balancing the half reactin S 2 O 3 2 S(s) (skeletal) the number f electrns that must be added is (a) 2 n the left (b) 2 n the right (c) 4 n the left (d) 4 n the right

11 Fr the reactin between permanganate in and xalate in in basic slutin, the unbalanced equatin is MnO 4 + C 2 O 2 4 MnO 2 (s) + CO 2 3 When this equatin is balanced, the number f OH ins is (a) 2 n the left (b) 2 n the right (c) 4 n the left (d) 4 n the right

12 The line representatin fr a vltaic cell utilizing the reactin 2 Cr(s) + 3 Cu 2+ 2 Cr Cu (s) is (a) (b) (c) (d) Cr(s) Cu 2+ Cr 3+ Cu(s) Cr(s) Cr 3+ Cu 2+ Cu(s) Cu(s) Cu 2+ Cr 3+ Cr(s) Cu(s) Cr 3+ Cu 2+ Cr(s)

13 The line representatin fr a vltaic cell utilizing the reactin 2 Fe 2+ + Cu 2+ 2 Fe 3+ + Cu (s) is (a) (b) (c) (d) Fe 2+ Fe 3+ Cu 2+ Cu(s) Fe 3+ Fe 2+ Cu 2+ Cu(s) Cu(s) Fe 3+,Cu 2+ Fe 2+ Cu(s) Pt(s) Fe 3+,Fe 2+ Cu 2+ Cu(s)

14 Cnsider the vltaic cell Pt(s) Sn 2+,Sn 4+ Fe 2+,Fe 3+ Pt(s) The ande reactin prduces (a) Sn 2+ (b) Fe 2+ (c) Sn 4+ (d) Fe 3+

15 Cnsider the vltaic cell Zn(s) Zn 2+ (aq) Cl (aq) Cl 2 (g) Pt(s) The cathde reactin prduces (a) Zn 2+ (b) Cl (c) Cl 2 (d) Pt

16 When a vltaic cell is running, catins in the salt bridge (a) mve int the cathde cmpartment (b) mve int the ande cmpartment (c) stay put

17 ε H + H 2 is (a) psitive (b) negative (c) zer

18 ε Zn 2+ Zn is the EMF f the cell (a) Zn(s) Zn 2+ (1 M) H + (1 M) H 2 (1 atm) Pt(s) (b) Pt(s) H 2 (1 atm) H + (1 M) Zn 2+ (1 M) Zn(s)

19 Fr the cell Zn(s) Zn 2+ (1 M) Cl (1 M) Cl 2 (g) Pt(s) the EMF is (a) + ε Zn 2+ Zn (b) + ε Zn 2+ Zn (c) - ε Zn 2+ Zn (d) - ε Zn 2+ Zn - ε Cl 2 Cl + ε Cl 2 Cl - ε Cl 2 Cl + ε Cl 2 Cl

20 If the cells Zn(s) Zn 2+ (1 M) Pb 2+ (1 M) Pb(s) and Pb(s) Pb 2+ (1 M) Cl (1 M) Cl 2 (g) Pt(s) are cnnected in series, the ttal EMF is (a) 2 ε Pb 2+ Pb (b) + ε Zn 2+ Zn (c) + ε Zn 2+ Zn (d) - ε Zn 2+ Zn - ε Zn 2+ Zn - ε Cl 2 Cl + ε Cl 2 Cl - 2 ε Pb 2+ Pb - ε Cl 2 Cl + ε Cl 2 Cl

21 If the cell Zn(s) Zn 2+ (1 M) H + (1 M) H 2 (1 atm) Pb(s) has an EMF f V and the cell Zn(s) Zn 2+ (1 M) Tl + (1 M) Tl(s) has an EMF f V, then ε Tl + Tl = (a) (b) (c) (d) ( ) V ( ) V ( ) V ( ) V

22 Given that and ε Ni ε Zn Ni Zn it is expected that = V = V (a) Ni will reduce Zn 2+ t Zn (b) Zn will reduce Ni 2+ t Ni (c) neither f the abve

23 Given that and the cell ε Cu ε Zn Cu Zn = V = V Cu(s) Cu 2+ (1 M) Zn 2+ (1 M) Zn(s) will run (a) frward (b) backward

24 Frm the standard electrde ptentials and and ε Fe ε Fe ε Fe Fe Fe Fe = V = V = V it fllws that the disprprtinatin f Fe 2+ (a) is (b) is nt spntaneus under standard cnditins.

25 Frm the standard electrde ptentials and and ε Cu ε Cu Cu Cu ε Cu + Cu = V = V = V it fllws that the disprprtinatin f Cu + (a) is (b) is nt spntaneus under standard cnditins.

26 Which f the fllwing statements abut a galvanic cell is true? (a) If ε < 0, then G > 0 (b) If ε > 0, then G > 0 (c) If ε < 0, then K eq > 1 (d) If ε > 0, then K eq > 1

27 A fuel cell invlves the ande reactin H 2 (g) 2 H + (aq) + 2 e and the cathde reactin 4 e + 4 H + (aq) + O 2 (g) 2 H 2 O (l) Since G f (H 2 O (l)) = kj/ml, (a) ε = + ( kj/ml) / 2 F (b) ε = + ( kj/ml) / 4 F (c) ε = ( kj/ml) / 2 F (d) ε = ( kj/ml) / 4 F

28 Cnsider the cell Cu(s) Cu 2+ (x M)) Cu 2+ (y M)) Cu(s) If y is decreased, the EMF f the cell will (a) increase (b) decrease (c) nt change

29 When a strip f Cu and a strip f Zn are pked int a piece f fruit r vegetable (r suspended in a beverage) withut direct cntact, a wire cnnecting them is fund t carry current. Given that ε Zn 2+ Zn = V & ε Cu 2+ Cu = V the crrect representatin f the cell is (a) Cu(s) Cu 2+ (aq) Zn 2+ (aq) Zn(s) (b) Zn(s) Zn 2+ (aq) Cu 2+ (aq) Cu(s) (c) Cu(s) H 2 (g) H + (aq), Zn 2+ (aq) Zn(s) (d) Zn(s) Zn 2+ (aq), H + (aq) H 2 (g) Cu(s) A mre acidic fruit, vegetable r beverage will (a) enhance (b) reduce (c) have n effect n the cell ptential

30 As the [Zn 2+ ] in the cell increases, the cell ptential will (a) increase (b) decrease (c) remain the same If the size f the Zn electrde is increased, the cell ptential will (a) increase (b) decrease (c) remain the same

31 Which f the fllwing cmmercial cells des nt have a cnstant discharge vltage? (a) Cd(s) Cd(OH) 2 (s) OH (aq) NiO(OH)(s) Ni(OH) 2 (s) (b) Li y C 6 (s) C 6 (s) Li + (aq) Li x CO 2 (s) Li x+y CO 2 (s) (c) Pb(s) PbSO 4 (s) HSO 4 (aq) PbO 2 (s) PbSO 4 (s) (d) Zn(s) Zn(OH) 2 (s) OH (aq) HgO(s) Hg(l) Fe(s)

32 Fr the cell Ni(s) Ni(NO 3 ) 2 (0.1 M)) KCl (0.2 M)) Cl 2 (0.5 atm) Pt(s) the value f the reactin qutient, Q, is (a) (0.5) (0.1) / (0.2) 2 and (b) (0.1) (0.2) / (0.5) 2 (c) (0.5) (0.1) 2 / (0.2) (d) (0.1) (0.2) 2 / (0.5) (a) ε = ε + (RT/2F) lnq (b) ε = ε (RT/2F) lnq (c) ε = ε + (RT/F) lnq (d) ε = ε (RT/F) lnq

33 A methanl fuel cell invlves the ande reactin H 2 O + CH 3 OH CO H e and the cathde reactin 4 e + 4 H + + O 2 2 H 2 O the vltage f this cell is (a) ε (RT/6F) ln (b) ε (RT/4F) ln (c) ε (RT/12F) ln (d) ε (RT/12F) ln p p O O p p pco 2 [ CH OH] 2 3 pco 2 [ CH OH] 2 3 O O p CO 2 2 [ CH OH] p CO [ CH OH] 3 2 3

34 Fr the reactin 2 I + Cl 2 2 Cl + I 2 the standard cell vltage is 0.82 V. The equilibrium cnstant fr this reactin is given by RT ln K eq = (a) 1 F (0.82 V) (b) 1 F (0.82 V) (c) 2 F (0.82 V) (d) 2 F (0.82 V)

35 Given that ε AgCl Ag = V ε AgBr Ag = V ε AgI Ag = V ε Ag + Ag = V which has the smallest K sp? (a) AgCl (b) AgBr (c) AgI K sp (AgBr) = (a) exp [ F ( ) V / RT ] (b) exp [ F ( ) V / RT ] (c) exp [ RT / F ( ) V ] (d) exp [ RT / F ( ) V ]

36 Thmas Edisn's first electricity meter was based n changes in mass f tw parallel Zn plates immersed in zinc sulfate slutin. In this device, transfer f a mle f Zn frm ne plate t the ther signifies passage f (a) 1 C (b) 1 F (c) 2 C (d) 2 F

37 Given that the charge f a mle f electrns is 96,485 C = 1 F, plating 1 mle f chrmium frm chrmic acid (H 2 CrO 4 ) using a 200 A current will take (a) 3 (96,485) / 200 (b) 200 / 3 (96,485) (c) 6 (96,485) / 200 (d) 200 / 6 (96,485) secnds.

38 T plate Cr(s) frm aqueus slutin under standard cnditins, ne can start with (a) Cr 3+ (b) Cr 2+ (c) either (d) neither given that ε Cr Cr = 0.74 V ε Cr 2+ Cr ε HOH 2 2 = 0.91 V = V

39 When a dilute slutin f Li 2 SO 4 is electrlyzed, the prducts frmed at the ande and cathde respectively are (a) S and Li (b) O 2 and Li (c) SO 2 and H 2 (d) O 2 and H 2 Pssibly useful infrmatin: ε O H O = V 2 2 ε HOH ε Li = V Li = V

40 Electricity frm a fuel cell that cnsumes H 2 and O 2 is used t drive the electrlysis f H 2 C 2 O 4 t CO 2 and H 2. Assuming that all the gases are held under the same cnditins, the vlume f O 2 cnsumed is (a) ne frth (b) half (c) the same as (d) twice the vlume f CO 2 prduced.