Calculate the reaction quotient Q,for the cell reaction.The measured cell voltage is given.balane the chemical equation by using the smallest whole number coefficients.
(a) Pt(s)Sn4+(aq),Sn2+(aq)||pb2+(aq),pb2+|C(graphite)(s) -E=+1.33V
To calculate the reaction quotient Q for a cell reaction, we need to determine the concentrations of the respective species involved in the reaction.
From the given cell reaction:
(a) Pt(s) | Sn4+(aq), Sn2+(aq) || Pb2+(aq), Pb2+ | C(graphite)(s)
We have two half-reactions:
1. Oxidation half-reaction: Sn4+(aq) + 2e- → Sn2+(aq)
2. Reduction half-reaction: Pb2+(aq) + 2e- → Pb2+(aq)
First, we need to balance the half-reactions by using the smallest whole-number coefficients. Here's how to balance each half-reaction:
1. Oxidation half-reaction: Since the reduction half-reaction involves Pb2+(aq), we need to balance the number of electrons on each side. To balance the electrons, we need to multiply the oxidation half-reaction by 2:
2Sn4+(aq) + 4e- → 2Sn2+(aq)
2. Reduction half-reaction: We already have the correct number of electrons on each side, so no balancing is required.
The overall balanced cell reaction is obtained by adding the two half-reactions together:
2Sn4+(aq) + 4e- → 2Sn2+(aq) (oxidation)
Pb2+(aq) + 2e- → Pb2+(aq) (reduction)
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2Sn4+(aq) + Pb2+(aq) → 2Sn2+(aq) + Pb2+(aq)
Now that we have the balanced cell reaction, we can determine the reaction quotient Q. Q is calculated using the concentrations (or activities depending on the context) of the products and reactants in the cell.
Since the concentrations are not provided, we cannot calculate the exact value of Q. However, we can still determine the relationship between the reactants and products using the given cell voltage (E = +1.33V):
E = E° - (RT/nF) * ln(Q)
In this equation, E° is the standard cell potential (which can be determined using standard reduction potentials), R is the ideal gas constant (8.314 J/(mol*K)), T is the temperature in Kelvin, n is the number of moles of electrons transferred in the balanced cell reaction, F is Faraday's constant (96485 C/mol), and ln is the natural logarithm function.
By rearranging the equation, we can solve for the reaction quotient Q:
Q = exp((E° - E) * (nF/RT))
To calculate Q, you need to know the standard cell potential (E°) for the cell reaction and the temperature at which the measurements were made. If these values are not provided, it is not possible to determine the value of Q.