Question

A principal constituent of petrol (gasoline) is iso-octane, C8H18. From the following thermodynamic data at 298 K what is the standard molar enthalpy of combustion of iso-octane in excess oxygen at 298 K? C3H78(1) + 12-02(g) + 8C02(g) +9H2O(1) Substance A; H/kJ mol-1 C8H18(I) -258.07 02(8) CO2(8) -393.51 H2O(1) -285.83 -3219 kJ mol-1 O-5462 kJ mol-2 - 7553 kJ mol-1 O -9210 kJ mol-1 A gas is contained in a horizontal cylinder with a moveable piston of cross-sectional area 0.33 m². The region outside the cylinder is at standard ambient temperature and pressure, 298 K and 1 bar. When 2040 J of heat flow into the gas, the internal energy of the gas increases by 1380 J. Calculate the distance through which the piston moves. You may assume friction is negligible. O2 cm 6 cm 10 cm 14 cm

Answer 1

1 Co Hig W) + 12 ! O Cq) - 8 CO, Cg) & 9 Hoe arren DHO (in kJ/mal) Ca Higled) - 258.07 Co Cg) - 39 3.51 Hold) -285.83 so Oh for Reactlen Ps Dhoma Coll Products) - (DH reactante) 2 [19- 285-83) + (8 » -3 93.51) | - > 0 + ( .) DH - 5462.48 kJ mal !! Correct option Pt B

Preasure al bar a los Parcala los N/m² Temperature 2 298k Croan. so clonal arca 20.33m² so, Preasure a force Area & 103 Nx (6.33 m²) a force as force a 33000 Newton work done a force & dlatance W z 33000 Newton & dextance. According to first claw of Thermodynamica daa all-w & (+30407) 2 (+13809) aw Toz- 6605 from egn & (-660 I) e (33000 N) * dlatane 2 l dlatance - 0.08m 8 an]