Home
Class 11
CHEMISTRY
Calculate enthalpy of formation of metha...

Calculate enthalpy of formation of methane `(CH_4)` from the following data :
(i) `C(s) + O_(2)(g) to CO_(2) (g) , Delta_rH^(@) = -393.5 KJ mol^(-1)`
(ii) `H_2(g) + 1/2 O_(2)(g) to H_(2)O(l) , Deta_r H^(@) = -285.5 kJ mol^(-1)`
(iii) `CH_(4)(g) + 2O_(2)(g) to CO_(2)(g) + 2H_(2)O(l), Delta_(r)H^(@) = -890.3 kJ mol^(-1)`.

Text Solution

Verified by Experts

We aimat at `: C(s) + 2H_(2)(g) rarr CH_(4)(g) , Delta_(f) H^(@) = ?`
Multiplying eqn. (ii) with 2, adding to eqn. (i) and then subtracting eqn. (iii) from the sum, i.e., operating eqn. (i) `+ 2 xx ` eqn. (ii) - eqn. (iii) , we get
`C(s) + 2H_(2)(g) - CH_(4)(g) rarr 0, Delta _(r) H^(@) - 393.5 + 2( -285.8) - ( - 890.3) = - 74.8 kJ mol^(_1)`
or `C_(s) + 2H_(2)(g) rarr CH_(4)(g), Delta _(f) H^(@) = -74.8 kJ mol^(-1)`
Hence, enthalpy of formation of methane is `: Delta_(f) H^(@) = - 74.8 kJ mol^(-1)`
Promotional Banner

Topper's Solved these Questions

  • THERMODYNAMICS

    PRADEEP|Exercise Sample Problem 2|5 Videos

  • THERMODYNAMICS

    PRADEEP|Exercise Sample Problem 3|1 Videos

  • THERMODYNAMICS

    PRADEEP|Exercise Problem 12|1 Videos

  • STRUCTURE OF ATOM

    PRADEEP|Exercise Competition Focus (JEE (Main and Advanced)/Medical Entrance (IX. Assertion And Reason Type Questions (Type II))|12 Videos

Similar Questions

Explore conceptually related problems

Calculate the enthalpy of formation of ethane from the following data : (i) C(s) + O_(2)(g) to CO_(2)(g) , Delta_(r)H^(@) = -393.5 kJ (ii) H_(2)(g) + 1/2 O_(2)(g) to H_(2)O(l), Delta_(r)H^(@) = -285.8 kJ (iii) C_(2)H_(6)(g) + 7/2O_(2)(g) to 2CO_(2)(g) + 3H_(2)O(l), Delta_(r)H^(@) = -1560.0 kJ

Calculate the enthalpy of formation of methane from the following data : C(s) + O_(2)(g) to CO_(2)(g) Delta_(r)H^(@) = -393.5 kJ 2H_(2)(g) + O_(2)(g) to 2H_(2)O(l) Delta_(r)H^(@) = -571.8 kJ CH_(4)(g) + 2O_(2)(g) to CO_(2)(g) + 2H_(2)O(l) Delta_(r)H^(@) = -890.3 kJ

Calculate the standard enthalpy of formation of acetylena from the following data: C(s)+O_(2)(g)to CO_(2)(g), DeltaH^(@)=-393.5KJmol^(-1) H_(2)(g)+(1)/(2)O_(2)(g)to H_(2)O(l),DeltaH^(@)=-285 .8KJmol^(-1) 2C_(2)H_(2)(g)+50_(2)(g)to 4Co_(2)(g)+2H_(2)O(l0, DeltaH^(@)=-2598.8KJmol^(-1)

Calculate the standard enthalpy of formation of acetylene from the following data : C_((g))+O_(2(g))rarr CO_(2(g)),DeltaH^(@)=-393kJ mol^(-1) H_(2(g))+(1)/(2)O_(2(g)) rarr H_(2)O_((l)),DeltaH^(@)=-285.8kJ mol^(-1) 2C_(2)H_(2(g))+5O_(2(g))rarr 4CO_(2(g))+2H_(2)O_((l)),DeltaH^(@)=-2598.8kJ mol^(-1) .

Calculate the enthalpy of combustion of glucose from the follwoing data : C("graphite") +O_(2)(g) to CO_(2)(g) Delta_(r)H^(@) = -395.0 kJ H_(2)(g) + 1/2 O_(2)(g) to H_(2)O(l) Delta_(r)H^(@) = - 269.4 kJ 6C("graphite") + 6H_(2)(g) + 3O_(2)(g) to C_(6)H_(12)O_(6)(s) Delta_(r)H^(@) = -1169.9 kJ