Question

The heat of combustion of C, S and

$CS_{2}are - 393.3kJ, - 293.7kJand - 1108.76kJ.$ what will be the heat of formation of $CS_{2}$?

• A. $- 128.02kJ$
• B. +970 kJ
• C. $+ 1108.7kJ$
• D. 12 kJ

Answer 1

Answer: (A)

$- 128.02kJ$

Answer 2

: $C + 2S \rightarrow CS_{2}$

$\Delta H = \sum\Delta H_{P} - \sum\Delta H_{R}$

$= - 1108.76 - \left\lbrack - 393.3 + 2 \times ( - 293.7) \right\rbrack$

$= - 1108.76 + 393.3 + 587.4$

$= - 128.02kJ$