InterviewSolution
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InterviewSolution
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Predict the sign of entropy change in each of the following `:` (i) `H_(2) ( ` at 298 K, 1 atm ) `rarr H_(2)` at 298 K, 10 atm) (ii) `H_(2)O( ` at 298K, 1 atm ) ` rarr H_(2)O` ( at 330K, 1atm) (iii) `2NH_(4)NO_(3)(s) rarr 2N_(2)(g)+4H_(2)O(g) +O_(2)(g)` (iv) Crystallization of copper sulphate from its saturated solution. (v) `2SO_(2)(g) +O_(2)(g) hArr 2SO_(3)(g)` |
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Answer» Entropy isa measure of randomness or disorder of a system. If randomness increases, entropy increases. (i) Gas at lower pressure has greater randomness than at high pressure ( compressed gas) at the same temperature. Hence, entropy decreases, i.e., `Delta S ` is -ve. (ii) Molecules at higher temperature have greater randomness at the same pressure . Hence, `Delta S` is `+` ve . (iii) Gaseous molecules have greater randomness than the solid . Hence, `Delta S` is `+ ` ve. (iv) `CuSO_(4)` crystals have ordered arrangement whereas ionsin the soluiton have greater randomness. Hence, `Delta S` is `-` ve. (v) There are 3 moles of two different gaseous reactants which have greater randomness than 2 moles of the only gaseous product, `SO_(3)` . Hence, randomness decrease, i.e., `Delta S` is `-` ve. |
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