Consider the reactions given below. On the basis of these reactions find out which of the
the algebraic relationships is correct?
1. | x=y | 2. | x=2y |
3. | x>y | 4. | x<y |
The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound is-
1. | Generally negative | 2. | Always positive |
3. | Zero | 4. | Never negative |
The enthalpy of sublimation of a substance is equal to-
1. Enthalpy of fusion + Enthalpy of vaporisation
2. Enthalpy of fusion
3. Enthalpy of vaporisation
4. Twice the enthalpy of vaporisation
Which of the following is not correct?
1. is zero for a reversible reaction.
2. is positive for a spontaneous reaction.
3. is negative for a spontaneous reaction.
4. is positive for a non-spontaneous reaction.
A necessary condition for an adiabatic change is-
1. ∆T = 0
2. ∆P = 0
3. q = 0
4. w = 0
The enthalpy of formation of all elements in their standard state is-
1. | Unity | 2. | Zero |
3. | Less than zero | 4. | Different for each element |
for combustion of methane is –x kJ mol–1.
The value of for the same reaction would be:
701 J of heat is absorbed by a system and 394 J of work is done by the system. The change in internal energy for the process is-
1. | 307 J | 2. | -307 J |
3. | 1095 J | 4. | -701 J |
The reaction of cyanamide, with dioxygen, was carried out in a bomb calorimeter, and ∆U was found to be at 298 K.
\(\small{\mathrm{NH}_2 \mathrm{CN}(\mathrm{s})+\frac{3}{2} \mathrm{O}_2(\mathrm{g}) \rightarrow \mathrm{N}_2(\mathrm{g})+\mathrm{CO}_2(\mathrm{g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l})}\)
The enthalpy change for the reaction at 298 K would be -
The amount of heat needed to raise the temperature of 60.0 g of aluminium from 35°C to 55°C would be -
(Molar heat capacity of Al is )