# Hydrogen has two isotopes : Hydrogen (H), whose nucleus has one proton only and deuteron (D) which has one proton

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Hydrogen has two isotopes : Hydrogen (H), whose nucleus has one proton only and deuteron (D) which has one proton and one neutron in the nucleus. Heavy water is formed when one or both hydrogen nuclei are replaced by Deuterons i.e. making it HDO or D2O. A scientist takes 40 percent (volume) of heavy water D2O and 60 percent (volume) H2O and thoroughly mixes it to make a total of 1000 L. D2O and H2O have nearly similar physical and chemical properties. The data given below is adjusted close to the realistic values so that the calculations become simple. Hence the data is valid for this question only. Also assume that HDO, the other form of heavy water, does not get formed.

The scientist is conducting an experiment to calculate the specific heat capacity of D2O in its frozen stage. As a first step he freezes it to exactly 0°C and then heats it slowly in a chamber which is thermally insulated from atmosphere. After providing 387160 kJ of energy the combination reaches 10ºC.

Given the data, calculate the specific heat of ice formed from D2O and give the graphical representation (qualitative, with appropriate values marked) of the entire process on the axes drawn on the graph paper provided in the answer sheet.

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Mix of H2O + D2O = 1000 L

amount of H2O = 600 L = 600 kg

amount of D2O = 400 L = 440 kg Total amount of heat required for the mixture = q1 + q2 + q3 + q4 + q5

387160 = 1760 x + 149600 + 11220 + 198000 + 24900

x = 1.95 KJ/Kg K.