Thermochemistry

1. For the reaction NaCl Na™ + CI” the change in enthalpy is called:

A) Heat of reaction B) Heat of formation

C) Heat of combustion D) Heat of solution

7. The branch of chemistry which deals with heat changes during chemical reactions is called:

A) Electrochemistry B) Thermochemistry 

C) Stoichiometry D) Titrimetry

3. VH will be given a negative sign in:

A) Exothermic reactions B) Dissociation reactions

C) Decomposition reactions D) Endothermic reactions

4. Hess’s law may be represented mathematically as:

A) | AH#0 B) ZAG > 0

C)ZAH=0 D) > AH <0

5. 12.0g of graphite is burnt in a bomb calorimeter and temperature recorded is 5K. Calculate the enthalpy of combustion (AHo c) of graphite if the heat capacity of the calorimeter is 90.0kJmol-1?

A) -440kJmol™1 B) -450kJmol 1!

C) -445kimol 1 D) -455kJmol™

6. Standard enthalpy of combustion of graphite at 25°C is —393.51kJmol-1 and that of diamond is —395.42kJmol-1 . What is the enthalpy change for the process?

A)-1.91 B) -2.1

C)+2.1 D) +1.91

7. Which of the following is an exothermic process?

A) Evaporation B) Thermal decomposition

C) Respiration D) Melting

8. Neutralization of 50cm? of 0.5M NaOH at 25°C with 50cm? of 0.5M HCI 25°C is raised to 31°C) Find enthalpy of neutralization (AHon). Specific heat of water (q)= 5kJ-1kg-1:

A) -125kJmol™1 B) -120kJmol~1!

C) -130kJmol~* D) -135kJmol 1

9. Which one of the following is the example of state function?

A) Heat B) Work

C) Mole D) Enthalpy

10. When pressure of 500Nm 2 is applied and volume change from 0.05m3 then work done by the system is:

A) 10] B) -10J

C) -235) D) +25]

11. The enthalpy of formation of MgO is

A) -393.7kJmol 1 B) -692kJmol 1

C) -285.7kJmol 1! D) -474.7kJmol~?!

12. One joule is equivalent to calorie:

A)1/4.184 B) 1/41.84

C) 4.184 D) 41.84

13. Glass calorimeter is used to determine:

A) AH’n B) AH?sol

C) AHCat D) AHOf

14. Evaporation of water is an exceptional case of:

A) Spontaneous reaction B) Non-spontaneous reaction

C) Decomposition reaction D) Hydrolysis reaction

15. Lattice energy is the amount of heat energy released in the formation of

one mole of ionic solid from its gaseous ions.

A) +376kJmol 1 B) -376kJmol~*

C) -411kJmol™1 D) +496kJmol~1!

16. ~ Hag) > H ; In the above reaction enthalpy change is:

A) Heat of neutralization B) Heat of solution

C) Heat of atomization D) Heat of sublimation

17. Born Haber’s cycle enables us to calculate:

A) Heat Energy B) Lattice Energy

C) Heat of hydration D) Heat of solution

18. Which of the following is / are limitations of AH??

A) It cannot tells us about rate of reaction

B) Cannot tell us whether reaction fast or slow

C) Says nothing about the kinetic stability of the product

D) All of these

19. If an endothermic reaction is allowed to take place very rapidly in the air, the temperature of the surrounding:

A) Remain constant B) Increase

C) Decrease D) First increase than decrease

20. For a given process, the heat change at constant pressure (qp) and at constant volume (qv) are related to each other as:

A) dp=qV B) gp < qv

C)gp > qv D) gp # qv

21. Thermodynamics does not deal with:

A) Heat of reaction B) Rate of reaction

C) Spontaneous reaction D) Entropy of reaction

27. Mathematical form of first law of thermodynamics is:

A) AS = grev/T B) AG = AH – TAS

C)AE=qg+w D) None of these

23. The enthalpy changes of formation of ethene and ethane are 52 kimol-1 and -85 kdmol-1 respectively at 298K. What is the enthalpy change of reaction at 298K for the following process?

A) -137kJmol 1 B) 33kimol™1

C) -33kdmol~? D) 137kJmol™1

24. Hess’s Law can be applied to determine:

A) Heat of formation B) Heat of combustion

C) Indirect measurement of AH D) All of these

75. Enthalpy of neutralization of all the strong acids and strong bases has the same value because:

A) Neutralization leads to the formation of salt and water

B) Strong acids and bases are ionic substances

C) Acids always give rise to H+ ions and bases always furnish OH- ions

D) The net chemical change involves the combination of H + and OH- ions to form 1 mole of water