1. Tardigrade
  2. Question
  3. Chemistry
  4. The electron affinity of a hypothetical element 'A' is 3 eV per atom. How much energy (in kcal) is released when 10 g of ' A ' is completely converted into A -ion in a gaseous state? (1 eV =23 kcal mol -1., Molar mass of .A =30 g )

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Q. The electron affinity of a hypothetical element '$A$' is $3\, eV$ per atom. How much energy (in kcal) is released when $10 \,g$ of ' $A$ ' is completely converted into $A ^{-}$ion in a gaseous state?
$\left(1 \,eV =23\, kcal\, mol ^{-1}\right.$, Molar mass of $\left.A =30\, g \right)$

Classification of Elements and Periodicity in Properties

Solution:

$\underset{30}{A} + e \rightarrow \underset{3\times 23\,kcal}{A^- + 3\,eV}$
$\therefore $ Energy released for conversion of $10 \,g$ gaseous $A$ into
$A ^{-}$ions $=\frac{3 \times 23}{30} \times 10=23\, kcal$