The heat of formation of C12H22O11 (s) , CO2 (g) and (H2O) are - 530 , -94.3 and- 68.3 kcalmol-1 respectively. The amount of C12H22O11 to supply 2700 kcal of energy is :
382.70 g
832.74 g
463.9 g
684.0 g
D.
684.0 g
C12H22O11 (s) + 12O2 (g) 12CO2 (g) + 11H2O (l)
= [12(CO2) + 11 (H2O)] - (C12H22O11)]
= - 1352.9 kcal
Thus, number of moles of C12H22O11 for getting 2700 kcal of heat.
= = 2 mol
= 2 X 242 = 684.0 g
Spontaneous adsorption of gas on solid surface is an exothermic process because :
H increases for system
S increases for gas
S decreases for gas
G increases for gas
Assertion : A reaction which is spontaneous and accompanied by decrease of randomness must be exothermic.
Reason : All exothermic reactions are accompanied by decrease of randomness.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, U and w correspond to
U < 0, w = 0
U < 0, w < 0
U > 0, w = 0
U > 0, w > 0
One mole of which of the following has the highest entropy ?
Liquid nitrogen
Hydrogen gas
Mercury
Diamond
1 mole of H2SO4 is mixed with 2 moles of NaOH .The heat evolved will be :
57.3 kJ
2 x 57.3 kJ
57.3/2 kJ
Cannot be predicted
One mole. of a perfect gas expands isothermally to ten times of its original volume. The change in entropy is :
0.1 R
2.303 R
10.0 R
100.0 R