InterviewSolution
Saved Bookmarks
| 1. |
How much energy is released when 6 mole of octane is burnt in air? Given `DeltaH_(f)^(@) " for " CO_(2)(g), H_(2)O(g) and C_(8)H_(18)(l)` respectively are - 490, -240 and + 160 kJ/molA. `- 6.2 kJ`B. `- 37.4 kJ`C. `- 35.5 kJ`D. ` - 20.0 kJ` |
|
Answer» Correct Answer - B `C+O_(2)rarrCO_(2) , DeltaH_(F)=-490 kJ//mol - (i)` `H_(2)+1//2O_(2)rarrH_(2)O, DeltaH_(F)=-240 kJ//mol - (ii)` `8C+9H_(2)rarrC_(8)H_(18), DeltaH_(F)=+160 kJ//mol - (iii)` applying (i)`xx8+(ii)xx9-(iii)` `C_(8)H_(18)+(25)/(2)O_(2)rarr8CO_(2)+9H_(2)O` `DeltaH^(@)=-3920-2160-160=-6240 kJ//mol` `=37440 kJ//mol =-37.4 kJ`. |
|