How to calculate heat evolved in mega joules.
Weight of glucose =0 .692good
Molar mass of glucose = 180g
Temperature increased = 25.22-21.71
=3.52 = 276.52K
No. Of miles of Glucose = 0.692/180 =0.0038moles
Heat capacity (given)= 650J/K
Heat evolved = heat capacity ×change in temperature
=650 × 276.52
=49738 J
Heat evolved per mol = heat evolved/total no.of moles
= 49738/0.0038
=13088947.4 J
1J = 10 ^-6 MG
Hence, 13088947 J = 13.089 MJ
Hence, when one mole of glucose is burnt than 13.089 MJ heat is evolved