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Since the enthalpy of elements in their ...

Since the enthalpy of elements in their natural state is taken to be zero, the heat of formation `(Delta_(f)H)` of compounds

A

Is always negative

B

Is a always positive

C

is zero

D

May be positive or negative

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The correct Answer is:
D
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ALLEN-THERMODYNAMICS -EXERCISE -3
  1. The enthalpy of a reaction at 273 K. is -3.57 KJ. What will be the ent...

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  2. For the reactions, (i) H(2)(g)+Cl(2)(g)rarr 2HCl(g)+ xKJ (ii) H(2)...

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  3. Since the enthalpy of elements in their natural state is taken to be z...

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  4. For the reaction H(2)+I(2)hArr2HI, DeltaH=12.40 kcal. The heat of fo...

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  5. AT 300K, the standard enthalpies of formation of C(6)H(5)COOH(s), CO(2...

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  6. Enthalpy of a compound is equal to its :- (When it is formed from cons...

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  7. Which of the following equations represent standard heat of formation ...

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  8. The enthalpy of formation of ammonia is -46.0 KJ mol^(-1) . The entha...

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  9. Given the enthalpy of formation of CO(2)(g) is -94.0 KJ, of CaO(s) i...

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  10. Given that standatrd heat enthalpy CH(4), C(2)H(4) and C(3)H(8) are -1...

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  11. The standard molar heat of formation of ethane, CO(2) and water are re...

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  12. Two atoms of hydrogen combine to form a molecule of hydrogen gas the e...

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  13. The Delta(f)H^(Theta) for CO(2)(g), CO(g), and H(2)O(g) are -393.5, -1...

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  14. The heats of combustion of carbon and carbon monoxide are -393.5 and ...

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  15. The standard heat of formation of CS(2)(I) will be, given that the sta...

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  16. The heat of combustion of CH(4(g)), C((g)) and H(2(g)) at 25^(@)C are ...

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  17. Standard enthalpy of formation is zero for

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  18. The standard heat for formation of NO(2) and N(2)O(4) are 8.0 and 2.0...

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  19. M is a metal that forms an oxide M(2)O,(1)/(2)M(2)O rarr M+(1)/(4)O(2)...

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  20. According to equation, C(6)H(6)(l)+15//2 O(2)(g)rarr 6CO(2)(g)+3H(2)O(...

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