The combustion of glucose takes place according to the equation:\[\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}, \Delta H = -72 \text{ k-cal}\]The energy required for the combustion of 1.6 g of glucose is