How much energy will 1 kg mass of wood yield on complete combustion if its calorific value were 15 kJ/g?

14 Why are fossils fuels classified as non-renewable sources of energy? What steps should be taken to conserve these sources? 15 The heat produced on complete combustion of 10 g of a fuel could raise the temperature of 2 kg of water from 20° C to 70° C. Calculate the calorific value of the fuel, if the specific heat capacity of water was 4.2 J/g ° C. Assume that the heat taken by the container is negligible. 17 Suppose the average solar energy incident on the green canopy (leaves) of a tree is 10⁸ J per day. The calorific value of the wood obtained from the tree could convert 1% of incident solar energy as wood, how many days will it take to produce 10 kg of wood? 18 State the conditions essential for combustion to take place.