Sucrose undergoes combustion as :
`C_(12)H_(22)O_(11)(s) + 12O_(2)(g) to 12 CO_(2)(g) + 11H_(2)O(l) + 5645 kJ "mol"^(-1)`
(i) How much energy will be liberated when 51.3 g of sucrose is burnt?
(ii) What is the energy required for the production of 5.472 g of sucrose?

Answer

(i) 846.75 kJ (ii) 90.32 kJ

Explanation

`C_(12)H_(22)O_(11)(s) + 12O_(2)(g) to 12CO_(2)(g) + 11 H_(2)O(l) + 5645 kJ`
1 mol of source = 342 g
(i) 1 mol or 342 g of surcrose on combustion liberate heat = 5645 kJ
51.3 g of sources on combustion liberate heat =` (5645 xx 51.3)/(342) = 846.75 kJ`
(ii) Energy is needed to produce surcose
342 g of sucrose require energy = 5645 kJ
5.472 g of sucrose require energy = `(5645)/(343) xx 5.472 = 90.32 kJ`.