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