Enthalpy sums

The heat of combustion of Rhombic S and Monoclinic S are -9.9 KJ and -8.7 KJ. The heat of transition from rhombic to monoclinic sulphur is

• - 18.6

• +18.6

• - 1.2

• +1.2

The difference in the heat of combustion at constant pressure and constant volume for the reaction

4SO_2(g) + 2O_2(g)→ 4SO_{3 (g)} at 300 K is

(R= 2 cal mol^-1K^-1)

• 1200

• -1200

• +600

• -600

Standard enthalpy of formation of CO, CO2 , N2O & N2O4 are -110,-393, 811, and 10 KJ/mole respectively. Find enthalpy for reaction N2O4 + 3CO → N2O + 3CO2

• -212

• +212

• -48

• +48

The amount of heat evolved when 500 cm3 of 0.1M HCl is mixed with 200cm3 of 0.2M NaOH

• 1.292

• 2.292

• 0.292

• 22.9

C +2S → Cs2 , ΔH = +117

C + O2 → Co2 Δ H = -393

S + O2 → SO2 , ΔH = -297

Find enthalpy of combustion of Cs2.

• -807

• -1104

• +1104

• +807

The reaction in which ΔH > ΔU is

• N_2(g) + 3H_2(g) → 2NH_3(g)

• CH_{4 (g)}+ 2O_{2 (g)} → CO_{2 (g)}+ 2H₂O_(l)

• N_{2 (g)} + O_{2 (g)}→ 2NO_(g)

• CaCO_3(s) → CaO_(s) + CO_{2 (g)}

• -98.69Kcal

• -235.43Kcal

• 194.91Kcal

• 98.69Kcal

• 260 Kcal/mol

• 180 Kcal/mol

• 130 Kcal/mol

• 80 Kcal/mol

• 8 KJ

• 88 KJ

• -16 KJ

• 196 KJ

• -3RT

• -4RT

• 4RT

• 3RT