Question

To make use of an ionic hydrate for storing solar energy, you place 422.0 kg of sodium sulfate decahydrate on your house roof. Assuming complete reaction and 100% efficiency of heat transfer, how much heat (in kJ) is released to your house at night

Answer 1

Complete Question

To make use of an ionic hydrate for storing solar energy, you place 422.0 kg of sodium sulfate decahydrate on your house roof. Assuming complete reaction and 100% efficiency of heat transfer, how much heat (in kJ) is released to your house at night? Note that sodium sulfate decahydrate will transfer 354 kJ/mol.

Answer:

The amount of energy released is $x = 4.63650 *10^5 KJ$

Explanation:

Number of moles is mathematically represented as

                         $n =\frac{mass}{Molar\ Mass}$

substituting $422.0kg = 422 *10^3g$ for mass of sodium sulfate decahydrate($Na_2 SO_4 \cdot 10H_2 O$), $322.2g/mol$ (This value is a constant )for the molar mass of sodium sulfate decahydrate

                        $n= \frac{422*10^3}{322.2}$

                           $= 1309.7 \ moles$

From the question we are told that

            1 mole of sodium sulfate decahydrate generates $354KJ$ of energy

         So  1309.7 mole would generate  x

Now stating the relation mathematically

                 1 mol → 354KJ

                 1309.7 mol → x

=>      $x = 4.63650 *10^5 KJ$