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3 years ago

14

An iron bar at 325 K is placed in a sample of water. The iron bar gains energy from the water if the temperature of the water is

1 answer:

noname [10]3 years ago

3 0

So what you need to do is to have all your answers in the same unit as the one in the question which is K then look for the one that is greater than that in the question because only then will it absorb heat from the water.

temp. of rod: 325K
(1) 65 K
(2) 45 K
(3) 65° C = (65 + 273) K = 338 K
(4) 45° C = (45 + 273) K = 318 K

⇒ option 3 is the answer

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<u>Explanation:</u>

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

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To calculate the EMF of the cell, we use the Nernst equation, which is:

$E_{cell}=E^o_{cell}-\frac{2.303RT}{nF}\log \frac{[Al^{3+}]^2}{[Cu^{2+}]^3}$

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$E_{cell}$ = electrode potential of the cell = ? V

$E^o_{cell}$ = standard electrode potential of the cell = +1.82 V

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F = Faraday's constant = 96500

$[Al^{3+}]=1.63M$

$[Cu^{2+}]=3.43M$

Putting values in above equation, we get:

$E_{cell}=1.82-\frac{2.303\times 8.314\times 315}{2\times 96500}\times \log(\frac{(1.63)^2}{(3.43)^3})\\\\E_{cell}=1.86V$

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