Chemistry, 11.12.2019 20:31 vibezkj

Which of the following redox reactions do you expect to occur spontaneously in the forward direction? check all that apply.
a. pb(s)+mn2+(aq)→pb2+(aq)+mn(s)
b. fe2+(aq)+zn(s)→fe(s)+zn2+(aq)
c. cr(s)+3ag+(aq)→cr3+(aq)+3ag(s)
d. cd2+(aq)+co(s)→co2+(aq)+cd(s)

Answers: 2

Show answers

Answers

Answer from: gisellekarime

The redox reactions that occur spontaneously are reaction b and reaction c.

Explanation:

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

Relationship between standard Gibbs free energy and standard electrode potential follows:

$\Delta G^o=-nFE^o_{cell}$

For a reaction to be spontaneous, the standard electrode potential must be positive.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$ .......(1)

Substance getting oxidized always act as anode and the one getting reduced always act as cathode.

For a:

The given chemical equation follows:

$Pb(s)+Mn^{2+}(aq.)\rightarrow Pb^{2+}(aq.)+Mn(s)$

Oxidation half reaction: $Pb(s)\rightarrow Pb^{2+}(aq.)+2e^-;E^o_{Pb^{2+}/Pb}=-0.13V$

Reduction half reaction: $Mn^{2+}(aq.)+2e^-\rightarrow Mn(s);E^o_{Mn^{2+}/Mn}=-1.18V$

Putting values in equation 1, we get:

$E^o_{cell}=-1.18-(-0.13)=-1.05V$

As, the standard electrode potential is coming out to be negative, this means that standard Gibbs free energy will be positive.

Thus, the reaction will be non-spontaneous.

For a:

The given chemical equation follows:

$Zn(s)+Fe^{2+}(aq.)\rightarrow Zn^{2+}(aq.)+Fe(s)$

Oxidation half reaction: $Zn(s)\rightarrow Zn^{2+}(aq.)+2e^-;E^o_{Zn^{2+}/Zn}=-0.76V$

Reduction half reaction: $Fe^{2+}(aq.)+2e^-\rightarrow Fe(s);E^o_{Fe^{2+}/Fe}=-0.44V$

Putting values in equation 1, we get:

$E^o_{cell}=-0.44-(-0.76)=0.32V$

As, the standard electrode potential is coming out to be positive, this means that standard Gibbs free energy will be negative.

Thus, the reaction will be spontaneous.

For c:

The given chemical equation follows:

$Cr(s)+3Ag^{+}(aq.)\rightarrow Cr^{3+}(aq.)+3Ag(s)$

Oxidation half reaction: $Cr(s)\rightarrow Cr^{3+}(aq.)+3e^-;E^o_{Cr^{3+}/Cr}=-0.74V$

Reduction half reaction: $Ag^{+}(aq.)+e^-\rightarrow Ag(s);E^o_{Ag^{+}/Ag}=0.80V$ ( × 3)

Putting values in equation 1, we get:

$E^o_{cell}=0.80-(-0.74)=1.54V$

As, the standard electrode potential is coming out to be positive, this means that standard Gibbs free energy will be negative.

Thus, the reaction will be spontaneous.

For d:

The given chemical equation follows:

$Co(s)+Cd^{2+}(aq.)\rightarrow Co^{2+}(aq.)+Cd(s)$

Oxidation half reaction: $Co(s)\rightarrow Co^{2+}(aq.)+2e^-;E^o_{Co^{2+}/Co}=-0.28V$

Reduction half reaction: $Cd^{2+}(aq.)+2e^-\rightarrow Cd(s);E^o_{Cd^{2+}/Cd}=-0.40V$

Putting values in equation 1, we get:

$E^o_{cell}=-0.40-(-0.28)=-0.12V$

As, the standard electrode potential is coming out to be negative, this means that standard Gibbs free energy will be positive.

Thus, the reaction will be non-spontaneous.

Hence, the redox reactions that occur spontaneously are reaction b and reaction c.

Answer from: Quest

Yes she is correct. the answer is completely correct

Answer from: Quest

10.063g / 10.00 ml = 1.0063 g/ml which rounds off to 4 sig figs as: 1.006 g/ml

Another question on Chemistry

Chemistry, 22.06.2019 09:00

Acrystal that absorvd water from air is (blank)a. aqueousb. homogenousc. hygroscopicd. efflorescent

Answers: 1

Answer

Chemistry, 22.06.2019 10:00

Miner's coal distributors does not mine coal itself, nor does it even store or handle the coal. instead, miner's solicits orders for low sulfur coal from other firms, then purchases the required amount from suppliers and directs them to ship the coal to its customers. what is miner's

Answers: 1

Answer

Chemistry, 22.06.2019 14:00

Which of the following is true about a carbonated soft drink? . the carbon dioxide is the solvent, and water is the solute.. the water is the solution, and carbon dioxide is the solvent.. the carbon dioxide is the solution, and the water is the solvent.. the water is the solvent, and the carbon dioxide is the solute.. .

Answers: 1

Answer

Chemistry, 22.06.2019 18:00

Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

Answers: 3

Answer

You know the right answer?

Which of the following redox reactions do you expect to occur spontaneously in the forward direction...

Questions