From the following data, calculate the enthalpy change for the combustion of cyclopropane at 298 K. The enthalpy of formation of CO2(g), H2O(l) and propene (g) are -393.5, -285.8 and 20.42 kJ mol-1 respectively. The enthalpy of isomerisation of cyclopropane to propene is -33.0 kJ mol-1.

1. -1021.32 kJ mol-1

2. -2091.32 kJ mol-1

3. -5021.32 kJ mol-1

4. -3141.32 kJ mol-1

Concept Questions :-

Hess's Law
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A gas mixture consisting of 3.67 litres of ethylene and methane on complete combustion at ${25}^{\circ }C$ produces 6.11 litres of CO2. Find out the amount of heat evolved on burning one litre of the gas mixture. The heats of combustion of ethylene and methane are -1423 and -891 kJ mol-1, respectively, at ${25}^{\circ }C$.

1. 30.88 kJ

2. 20.28 kJ

3. 50.88 kJ

4. 60.18 kJ

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The standard enthalpy of combustion at ${25}^{\circ }C$ of hydrogen, cyclohexene (C6H10) and cyclohexane (C6H12) are -241, -3800 and -3920 kJ mol-1, respectively. Calculate the standard enthalpy of hydrogenation of cyclohexene.

1. -131 kJ mol-1

2. -155 kJ mol-1

3. -167 kJ mol-1

4. -121 kJ mol-1

Concept Questions :-

Thermochemistry
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The bond dissociation enthalpy of gaseous H2, Cl2 and HCl are 435, 243 and 431 kJ mol-1, respectively. Calculate the enthalpy of formation of HCl gas.

1. -92 kJ mol-1

2. -82 kJ mol-1

3. -21 kJ mol-1

4. -55 kJ mol-1

Concept Questions :-

Enthalpy and It's Type
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Difficulty Level:

The enthalpies of the following reactions are shown alongwith.

Calculate the O-H bond energies for the hydroxyl radical.

1. 223.18 kJ mol-1

2. 423.38 kJ mol-1

3. 513.28 kJ mol-1

4. 113.38 kJ mol-1

Concept Questions :-

Thermochemistry
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Difficulty Level:

The heat of combustion of ethylene at ${17}^{\circ }C$ and at constant volume is -332.19 kcals. What is the value at constant pressure, given that water is in liquid state ?

1. -131.25 k cals

2. -412.23 k cals

3. -534.12 k cals

4. -333.35 k cals

Concept Questions :-

Enthalpy and It's Type
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

For a reaction,  is given by the equation  in the temperature range 300-600 K. The enthalpy of the reaction at 300 K -s -25.0 KJ. Calculate the enthalpy of the reaction at 450 K.

Also

1. -10.12 kJ

2. -28.32 kJ

3. -18.72 kJ

4. -8.21 kJ

Concept Questions :-

Enthalpy and It's Type
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A certain vessel X has water and nitrogen gas at a total pressure of 2 atm. and 300 K. All the contents of the vessel are transferred to another vessel Y having half the capacity of the vessel X. The pressiure of N2 in this vessel was 3.8 atm. at 300 K. The vessel Y is heated to 320 K and the total pressure observed was 4.32 atm. Calculate the enthalpy of vapourisation of water assuming it to be independent of temperature. Also assume the volume occupied by the gases in a vessel is equal to the volume of the vessel.

1. 39.637 kJ mol-1

2. 19.531 kJ mol-1

3. 396.37 kJ mol-1

4. 3.9127 kJ mol-1

Concept Questions :-

Enthalpy and It's Type
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Difficulty Level:

The intermediate SiH2 is formed in the thermal decomposition of silicon hydrides. Calculate $∆{H}_{f}^{\circ }$ of SiH2 given the following reactions

1. 353 kJ/mol

2. 321 kJ/mol

3. 198 kJ/mol

4. 274 kJ/mol

Concept Questions :-

Thermochemistry
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Difficulty Level:

State which of the following statements is true ?

1. First law of thermodynamics is not adequate in predicting the direction of the process.

2. In an exothermic reaction, the total enthalpy of the products is greater than that of reactants.

3. The standard enthalpy of diamond is zero at 298 K and 1 atm pressure.

4. It is possible to calculate the value of $∆H$ for the reaction ${H}_{2}\left(g\right)+B{r}_{2}\left(l\right)\to 2HBr\left(g\right)$ from the bond enthalpy data.

Concept Questions :-

First Law of Thermodynamics