CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

The heat liberated when $$1.89$$ g of benzoic acid is burnt in a bomb calorimeter at $$25^o$$C increases the temperature of $$18.94$$ kg water in calorimeter by $$0.632^o$$C. If the specific heat of water at $$25^o$$C is $$0.998$$ cal $$g^{-1}$$ $$deg^{-1}$$, then the value of the heat of combustion of benzoic acid is:


A
881.1 kcal
loader
B
771.12 kcal
loader
C
981.1 kcal
loader
D
871.2 kcal
loader

Solution

The correct option is B $$771.12$$ kcal
Mass of benzoic acid, $$m=1.89$$ g
$$T=25^0C$$
Mass of water,$$m_{H_2O}=18.94\ kg=18940\ g$$
$$\Delta T=0.632^0C$$
specific heat of water, $$C_V=0.998 cal/g$$
heat gained by water,$$q=mC\Delta T$$
$$q=18940 \times 0.998 \times 0.632$$
$$q=11946.14\ cal$$
Heat released by the caloriemeter= heat gained by water
thus heat released by 1.89 g of benzoic acid = $$11946.14$$ cal
since heat of combustion=heat released by 1 mol of benzoic acid
thus heat released by $$1$$ mol or $$122$$ g of benzoic acid$$\frac{11946.14}{1.89} \times 122$$
$$=771126.5cal=771.12 kcal$$ heat is liberated from combustion of benzoic acid

Chemistry

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
People also searched for
View More



footer-image