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Thermodynamics

Question
CBSEENCH11006281
Wired Faculty App

Calculate the equilibrium constant for the reaction at 400 K:

space space 2 NOCl left parenthesis straight g right parenthesis space space space rightwards harpoon over leftwards harpoon space space space 2 NO left parenthesis straight g right parenthesis space plus space Cl subscript 2 left parenthesis straight g right parenthesis
increment subscript straight r straight H to the power of 0 space equals space 77.2 space KJ space mol to the power of negative 1 end exponent space and increment subscript straight r straight S to the power of 0 space equals space 122 space JK to the power of negative 1 end exponent space mol to the power of negative 1 end exponent space 400 space straight K.
            
                                
       
       

Solution

We know, 
       increment subscript straight r straight G to the power of 0 space equals space increment subscript straight r straight H to the power of 0 space minus space straight T increment subscript straight r straight S to the power of 0                    ...(1)
   Now space space space increment straight H to the power of 0 space equals space 77.2 space KJ space mol to the power of negative 1 end exponent space equals space 77200 space straight J space mol to the power of negative 1 end exponent space space space space space space space space space space space space space space straight T space equals space 400 straight K space and space increment subscript straight r straight S to the power of 0 space equals space 122 space JK to the power of negative 1 end exponent space mol to the power of negative 1 end exponent
Substituting the values in (1), we have,
       increment subscript straight r straight G to the power of 0 space equals space 77200 space straight J space mol to the power of negative 1 end exponent space minus space left parenthesis 400 space straight K right parenthesis space cross times space left parenthesis 122 space JK to the power of negative 1 end exponent space mol to the power of negative 1 end exponent right parenthesis space space space space space space space space equals space 77200 space straight J space mol to the power of negative 1 end exponent space minus space 48800 space straight J space mol to the power of negative 1 end exponent space space space space space space space space equals space 28400 space straight J space mol to the power of negative 1 end exponent
Now space space space increment subscript straight r straight G to the power of 0 space equals space minus 2.303 space RT space log space straight K 28400 space straight J space mol to the power of negative 1 end exponent space equals space minus 2.303 space cross times space left parenthesis 8.314 space JK to the power of negative 1 end exponent space mol to the power of negative 1 end exponent right parenthesis space space space space space space space space space space space space space space space space space space space space space space space space space cross times space left parenthesis 400 space straight K right parenthesis space log space straight K therefore space space log space straight K space equals space fraction numerator 28400 space straight J space mol to the power of negative 1 end exponent over denominator left parenthesis 2.303 space cross times space 8.314 space cross times space 400 right parenthesis straight J space mol to the power of negative 1 end exponent end fraction space space space space space space space space space space space space equals space minus 3.708
log space straight K space equals space minus 4 plus 4 minus 3.708 space equals space 4 with bar on top.292 space space space straight K space equals space Antilog space left parenthesis stack 4. with bar on top space 292 right parenthesis space space space space space space space space equals space 1.96 space cross times space 10 to the power of negative 4 end exponent

Some More Questions From Thermodynamics Chapter

What do you understand by the terms: the system and surroundings?

Classify the following into different types of systems:
(i) Tea placed in a cup
(ii) Tea placed in a tea-pot
(iii) Tea placed in a thermosflask. 

Define a closed system.

Define an isolated system.

Define intensive properties.

Define extensive properties.

Why all living systems need to be 'open systems'?

Define state variables of a system.

From thermodynamic point of view, to which system the animals and plants belong?

What is a state function?

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