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Calculate w, q and ∆U when 0.75 mol of an ideal gas expands isothermally and slowly at 27°C from a volume of 15 L to 25 L.
Carbon monoxide is allowed to expand isothermally and reversibly from 10 m3 to 20 m3 at 300 K and work obtained is 4.754 kJ. Calculate the number of moles of carbon monoxide.
If water vapour is assumed to be perfect gas, molar enthalpy change at 1 bar and 100°C is 41 kJ mol–1. Calculate the internal energy when
(i) 1 mol of water is vaporized at 1 bar pressure and 100°C.
(ii) 1 mol of water is converted into ice.
The enthalpy of formation of gaseous iodine is 62.5 kJ mol–1 at 25°C. What will be the enthalpy of sublimation of iodine at 25°C?
Calculate the amount of work done in each of following cases:-
(i) One mole of an ideal gas contained in a bulb of 10 litre capacity at 1 atm is allowed to enter into an evacuated bulb of 100 litre capacity.
(ii) One mole of a gas is allowed to expand from a volume of 1 litre to a volume of 5 litre against the constant external pressure of 1 atm (1 litre atm = 101.3 J)
Calculate the internal energy change (∆U) in each case if the process were carried out adiabatically.
Is the bond energy of all the four C–H bonds in CH4 molecule equal? If not then why? How is the C–H bond energy then reported?
A 5-litre cylinder contained 10 moles of oxygen gas at 27°C. Due to sudden leakage through the hole, all the gas escaped into the atmosphere and the cylinder got empty. If the atmospheric pressure is 1.0 atmosphere, calculate the work done by the gas.
Express the change in internal energy of a system when
(i) No heat is absorbed by the system from the surroundings, but work (w) is done on the system. What type of wall does the system have?
(ii) No work is done on the system, but q amount of heat is taken out from the system and given to the surroundings. What type of wall does the system have?
(iii) w amount of work is done by the system and q amount of heat is supplied to the system. What type of system would it be?
Two moles of an ideal gas initially at 27°C and one atmospheric pressure are compressed isothermally and reversibly till the final pressure of the gas is 10 atm. Calculate q, w and ∆V fro the process.
Calculate the internal energy change in each of the following cases:-
(i) A system absorbed 15 kJ of heat and does 5 kJ of work.
(ii) 5 kJ of work is dose on the system and 15 kJ of heat is given out by the system.
Calculate the enthalpy change for the process:
CCl4(g) → C(g) + 4Cl(g)
And calculate bond enthalpy of C–Cl in CCl4(g)
Given:
ΔvapH°(CCl4) = 30.5 kJ mol−1
ΔfH°(CCl4) = −135.5 kJ mol−1
ΔaH°(C) = 715.0 kJ mol−1 (enthalpy of atomization)
ΔaH°(Cl2) = 242 kJ mol−1
A swimmer coming out from a pool is covered with a film of water weighing about 18 g. How much heat must be supplied to evaporate this water at 298 K? Calculate the internal energy of vaporization at 100°C. ∆vapH° for water at 373 K = 40.66 kJ mol–1.
(a) Calculate the energy needed to raise the temperature of 10.0 g of iron from 25°C to 500°C if specific heat capacity of iron is 0.45 J (°C)–1 g–1.
(b) What mass of gold of specific heat capacity 0.13 J (°C)–1 g–1 can be heated through the same temperature difference when supplied with the same amount of energy as in (a)?
5.6 dm3 of an unknown gas at S.T.P. requires 52.25 J of heat to raise its temperature by 10°C at constant volume. Calculate Cv , Cp an atomicity of the gas.
Calculate the amount of heat evolved when
(i) 500 cm3 of 0.1 M hydrochloric acid is mixed with 200 cm3 of 0.2 M sodium hydroxide solution
(ii) 200 cm3 of 0.2 M sulphuric acid is mixed with 400 cm3 of 0.5 M potassium hydroxide solution.
Assuming that the specific heat of water is 4.18 J K–1 g–1 and ignoring the heat absorbed by the container, thermometer, stirrer etc., what would be the rise in temperature in each of the above cases?
Calculate the enthalpy change for the reaction H2(g) + Br2(g) → 2HBr(g)
Given that the bond enthalpies of H–H, Br–Br and H–Br are 435, 192 and 364 kJ mol–1 respectively.