200 ml of KOH and 200 ml of HNO3 of same molarity are mixed together and liberated 3.426 kJ of heat. Determine the molarity of each solution.

 

Consider the chemical reaction at 300 K H2 (g) + Cl2 --> HCl(g) ΔH= -185KJ/mole calculate ΔU if 3 mole of H2 completely react with 3 mole of Cl2 (g) to form HCl.

 

                           H₂ (g)+Cl_{2 -->}  HCl(g) ΔH= -185KJ/mole

                                       Δng=0

                                   ΔH= ΔU+ ΔngRT

                                  ΔH= ΔU

                       ΔH_R= -185 KJ/mole ,ΔU_R= -185 KJ/mole

                       H₂ (g)+Cl_{2 -->} HCl(g) ΔH= -185KJ/mole

                         3 mole       3 mole

            Hence           ΔU= -185 X 3 KJ/Mole

What is the relation between change in enthalpy (dH ) and change in internal (dE) for combustion of methan ?

For the given reaction:

                        CH₄(g) + 2O₂(g) ---------> CO₂(g) + 2H₂O(l)

                                          dH = dE + dnRT

                            Dn = no. of mole of products - no. of moles of reactants = 1– 3 = –2

                                             DH = DE – 2RT

1 mole of a real gas is subjected to a process from (2 bar, 40 lit.,300K) to (4 bar, 30 lit., 400 K). If change in internal energy is 35 kJ then calculate enthalpy change for the process.

                       DH = DU + D(PV)

                        D(PV) = P₂V₂ – P₁V₁

                                          = 4 × 30 – 2 × 40

                                   = 40 liter -bar = 4 kJ

                  so      DH = 35 + 4 = 24 kJ

Calculate the work performed when 2 moles of hydrogen expand isothermally and reversibly at 25”C from 15 to 50 litres.