Butane, c4h10 has a standard enthalpy of combustion= -2881 kj/mol

for part b, the enthalpy change when 4.000 g of butane is completely burned was -198.3 kj

assuming the specific heat capacity of water to be 4.200 j/g k, and that in such a reaction only 63.15% of the energy generated is actually transferred to the water, calculate the change in temperature of 2.000kg of water that is heated by burning the butane in part b above.

14.91 K.

Explanation:

Q = m.c.ΔT,

where, Q is the amount of heat transferred to water.

m is the mass of the amount of water (m = 2.0 kg = 2000.0 g).

c is the specific heat capacity of water (c = 4.2 J/g.K).

ΔT is the change in temperature due to the transfer of butane burning.

Q from 4.000 g of butane is completely burned is - 198.3 kJ = 198300 J.

The negative sign symbolizes the the enthalpy change is exothermic, which means that the energy is released.

∴ Q (the amount of heat transferred to water) = (198300 J)(0.6315) = 125226.45 J.

∴ ΔT = Q/m.c. = (125226.45 J) / (2000.0 g)(4.2 J/g.K) = 14.9079 K ≅ 14.91 K.

This means that the temperature is increased by 14.91 K.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.