At 298 K, the enthalpy of fusion of a solid (X) is 2.8 kJ mol$-$1 and the enthalpy of vaporisation of the liquid (X) is 98.2 kJ mol$-$1. The enthalpy of sublimation of the substance (X) in kJ mol$-$1 is _____________. (in nearest integer)
Answer (integer)
101
Solution
<p>The enthalpy of sublimation is the total amount of energy required to convert a solid directly into a gas. This can be calculated by summing the enthalpy of fusion (solid to liquid) and the enthalpy of vaporization (liquid to gas). Mathematically, this relationship is represented as:</p>
<p>$$ \Delta H_{\text{sublimation}} = \Delta H_{\text{fusion}} + \Delta H_{\text{vaporization}} $$</p>
<p>Given:</p>
<p><p>Enthalpy of fusion, $\Delta H_{\text{fusion}} = 2.8 \, \text{kJ mol}^{-1}$</p></p>
<p><p>Enthalpy of vaporization, $\Delta H_{\text{vaporization}} = 98.2 \, \text{kJ mol}^{-1}$</p></p>
<p>Substitute these values into the equation:</p>
<p>$$ \Delta H_{\text{sublimation}} = 2.8 \, \text{kJ mol}^{-1} + 98.2 \, \text{kJ mol}^{-1} = 101.0 \, \text{kJ mol}^{-1} $$</p>
<p>Therefore, the enthalpy of sublimation of the substance (X) is approximately 101 kJ mol<sup>$-1$</sup>.</p>
About this question
Subject: Chemistry · Chapter: Thermodynamics · Topic: Zeroth and First Law
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