Chemistry

Problem

Dry ice (solid CO

_2

) sublimates directly to gas at

-78.5\,^{\circ}\!\text{C}

. How much energy, in kilojoules, is absorbed when

0.250\,\text{g}

of CO

_2

sublimes at this temperature? (Molar mass of CO

_2

=44.01\,\text{g mol}^{-1}

; molar enthalpy of sublimation

=25.2\,\text{kJ mol}^{-1}

.) a)

-0.143\,\text{kJ}

0.143\,\text{kJ}

6.30\,\text{kJ}

1.43\,\text{kJ}