The combustion of how many moles of ethane (c2h6) would be required to heat 851 g of water from 25.0°c to 98.0°c? (assume liquid water is formed during the combustion.)

Answer : The number of moles of ethane required will be 0.166 mole.

Explanation :

First we have to calculate the heat absorbed by water.

where,

q = heat absorbed = ?

m = mass of water = 851 g

c = specific heat of water =

= final temperature =

= initial temperature =

Now put all the given values in the above formula, we get:

        (1 kJ = 1000 J)

Now we have to calculate the moles of ethane required.

where,

= enthalpy of combustion of ethane = 1560.7 kJ/mol (standard value)

q = heat absorbed = 259.67 kJ

n = number of moles of ethane = ?

Therefore, the number of moles of ethane required will be 0.166 mole.