How much energy (in kcal) is involved when 5.2 g of water at 0.0oC is converted to ice? Enter only the numeric value for your answer (no units).

Respuesta :

Answer:

[tex]Q=0.41kcal[/tex]

Explanation:

Hello.

In this case, since the energy involved during this process is associated to the freezing enthalpy of water at the freezing point of water (0.0 °C) and is computed via:

[tex]Q=m\Delta _{freezing}H[/tex]

It is known that the freezing enthalpy of water is -333.3 J/g, therefore, the involved heat is:

[tex]Q=5.2g*-333.33\frac{J}{g}\\ \\Q=-1733.33J[/tex]

Clearly, it is negative since freezing requires the removal of energy, which means it is negative based on the first law of thermodynamics. Finally, the energy in kcal turns out:

[tex]Q=1733.33J*\frac{1kcal}{4184kJ}\\ \\Q=0.41kcal[/tex]

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