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The enthalpy of the elements in their standard states is taken as zero. So the enthalpy of formation of a compound may be

A. negative

B. positive

C. zero

D. negative or positive

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  1. The apparatus used for measuring the heat changes is known as ...
  2. 1 Joule is equal to
  3. In a spontaneous irreversible process, the total entropy of the system & its surroundings
  4. Internal energy of the elements is assigned a value of................................cal per mole at…
  5. 10 gm of ice at 0°C is placed into 100 gm of water at 50°C. Hie temperature of water after the…
  6. The heat of neutralisation of a strong acid and a strong base is equal to......................K.Cal gm eq-1
  7. For a reaction 2 SO2g+O2g→2 SO3;g∆G°=-141.8 KJ-1So the driving force…
  8. If temperature is kept constant during the reaction, the process is said to be.......................
  9. The enthalpy of the elements in their standard states is taken as zero. So the enthalpy of formation…
  10. Heat of Reaction between sodium hydroxide and hydrochloric acid is 57.32 KJ mole-1. So heat of…
  11. In a thermal decomposition reaction, sign of ∆H may be...
  12. On burning hydrogen in an atmosphere of chlorine, 1.65 gm of HC1 was obtained and 1 Kcal of heat was…
  13. The solution energy of AI+++ion is more than that of Mg+++ due to...
  14. 35.5 gm of chlorine gas is allowed to expand freely in vacuum at 25°C. Then AH for this process…
  15. In reaction Cs+O2g→CO2g ∆H=-94.3 K cal mol-1
  16. The total heat content of a system is known as....
  17. Heat of combustion of S (Rhombic) and S (monoclinic) are -297.5 KJ and -300 KJ mole-1 respectively.…
  18. Heat of neutralisation of HCI and NaOH is -57.32 KJ per gram equivalent and that of acetic acid and…
  19. Heat of fusion of a molecular solid is
  20. Heat of combustion of methane and ethane are -291.7 Kcal & — 441.2 Kcal respectively:
  21. A person requires 2870 Kcal of energy for leading a normal life. If heat of combustion of cane sugar…
  22. Heat of reaction
  23. For the reaction C+O2→CO2        ∆H1=394 KJ mole-12CO+O2→2CO2∆H2=569 KJ∆H for 1 mole formation of CO is...?
  24. A person requires 2870 Kcal of energy for leading a normal life. If heat of combustion of cane sugar…
  25. The highest temperature at which vapour pressure of a liquid can be measured is..
  26. The factor that does not influence the heat of reaction is...
  27. The molar entropy of vaporisation of a liquid at its boiling point is
  28. The heat change taking place in the reactionH2 OI→H2Og,∆HfH2 Og=-57K Cal∆HfH2 OI=68.3K Cal is..?