Enthalpies for Different Types of Reactions

IMPORTANT

Enthalpies for Different Types of Reactions: Overview

This topic covers concepts such as Enthalpy of Reaction, Standard Enthalpy of Reactions, Factors Influencing Enthalpy of Reaction, Role of Physical State of Chemicals in Enthalpy of Reaction, Enthalpy of Sublimation, Kirchhoff's Equation, etc.

Important Questions on Enthalpies for Different Types of Reactions

MEDIUM
IMPORTANT

From the data of following bond energies:

 HHbondenergy:431.37kJmol1C=Cbondenergy:606.10kJmol1CCbondenergy:336.49kJmol1CHbondenergy:410.50kJmol1

Calculate the enthalpy of the following reaction in kJmol1.

Question Image 

 

                               

EASY
IMPORTANT

Given that bond energies of HH  and  ClCl  are  430 kJmol1and240kJmol1respectively and ΔHf for HClis −90 kJmol1, bond enthalpy of HCl is:

                               

EASY
IMPORTANT

For which one of the following equations is ΔHreaction° equal to ΔHf° for the product?

                               

MEDIUM
IMPORTANT

What is the enthalpy change for,

2H2O2(l)2H2O(l)+O2(g) if heat of formation of  H2O2(l)  and  H2O(l)  are -188 and -286 kJ/molrespectively (in standard conditions)?

EASY
IMPORTANT

The values of heat of formation of  SO2​​ andSO3 are –298.2 kJ and –98.2 kJ. The enthalpy change of the reaction

 SO2+12O2SO3 will be

                               

EASY
IMPORTANT

Assume each reaction is carried out in an open container. For which reaction will ΔH=ΔE ?

                               

MEDIUM
IMPORTANT

The absolute enthalpy of neutralisation of the reaction:

 MgOs+2HClaqMgCl2aq+H2Ol will be:

[Consider the actual value instead of magnitude].

                               

EASY
IMPORTANT

For the reaction:

C3H8(g)+5O2(g)3CO2(g)+4H2O(l)

at constant temperature, ΔHΔE is:

                               

EASY
IMPORTANT

How many of the following have standard heat of formation value of zero.

(i) Br2l

(ii) CO2g

iii C(graphite) 

(iv) Cl2l

(v) Cl2g

(vi) F2g

(vii) Fg

(viii) I2g

ix S(monoclinic )

x N2(g)

(xi) Pblcak

(xii) Pred

(xiii) CH4

MEDIUM
IMPORTANT

In Kirchhoff's equation, the term Cv is used instead of Cp at constant volume.

MEDIUM
IMPORTANT

Kirchhoff's equation at constant volume is : 

MEDIUM
IMPORTANT

The variation of U with temperature is expressed by Kirchoff's equation.

MEDIUM
IMPORTANT

Temperature affects the  enthalpy change of a reaction.

HARD
IMPORTANT

Write the Kirchhoff's equation at constant volume and at constant pressure.

HARD
IMPORTANT

Specific heat capacity is not the parameter that is used to relate the enthalpy of a reaction and temperature.

MEDIUM
IMPORTANT

Describe the effect of temperature on enthalpy of reaction.

MEDIUM
IMPORTANT

What happens to the enthalpy of the system if its temperature increases?

MEDIUM
IMPORTANT

Give the Kirchhoff's equation at constant volume.

MEDIUM
IMPORTANT

Which of the following is not the equation of Kirchhoff's law?

MEDIUM
IMPORTANT

Which law relates the temperature and enthalpy change of a reaction?