An ecology student investigates the energy content of a dry hazelnut using a school-laboratory calorimeter setup.
They burn a single hazelnut of mass 0.75 g0.75\text{ g}0.75 g beneath a boiling tube containing 30.0 g30.0\text{ g}30.0 g of water. The temperature of the water rises from an initial temperature of 21.2∘C21.2^\circ\text{C}21.2∘C to a maximum temperature of 54.8∘C54.8^\circ\text{C}54.8∘C.
If the specific heat capacity of water is 4.2 J g−1 ∘C−14.2\text{ J g}^{-1}\text{ }^\circ\text{C}^{-1}4.2 J g−1 ∘C−1, calculate the heat energy transferred to the water by the burning hazelnut in Joules (J\text{J}J).
Calculate the calculated energy content of the hazelnut per gram of its mass in kJ g−1\text{kJ g}^{-1}kJ g−1.
Suggest why the calculated energy content is likely to be lower than the actual energy stored in the hazelnut, and state two practical improvements to the experimental setup to minimize this difference.
Name the main type of food molecule stored in hazelnuts, and explain why it is essential for the seed to have a food store during the initial stages of germination.
