To find the energy content of cashews, you carry out an calorimetric experiment,
ID: 1067822 • Letter: T
Question
To find the energy content of cashews, you carry out an calorimetric experiment, similar to lab experiment #9. The heat capacity (Specific heat) of water is C_p = 4.184 J/g degree C. The experimental data are as follows: Mass of cashew nut before burning: 0.550 g Mass of cashew nut after burning: 0.0500 g Mass of water: 200.00 g Temperature increase of water (AT) is 7.00 degree C Calculate the heat absorbed by the water, q, using the equation, q = Cp * m * delta T Calculate the energy content of cashew in units of kJ/g from this experiment. Calculate the molality of a solution which is 1.45 g of biphenyl (C_6H_5)_2 is dissolved 60.0 g of benzene C_6H_6 (t) (C: 12.011; H: 1.008)Explanation / Answer
(6)
q = Cp * m * (t2 - t1)
q = 4.184 * 200.0 * 7.00 = 5857.6 J = 5.858 kJ
(7)
Change in mass of cashew nut = 0.550 - 0.0500 = 0.500 g.
Energy release by 1 g. of cashew nut = 5.858 / 0.5 = 11.72 kJ / g.
(8)
moles of biphenyl = 1.45 / 154.212 = 0.009403 mol
Mass of benzene = 60 g. = 0.060 kg
molality = moles of solute / kg of solvent
m = 0.009403 / 0.060
m = 0.1567 m