A solution of 6.3 g of haemoglobin (molar mass = 64,000 g/mol) in 25 ml of solution shows a temperature rise of 0.03°C for complete oxygenation. Each mole of haemoglobin binds 4 moles of oxygen. If th

Question

A solution of 6.3 g of haemoglobin (molar mass = 64,000 g/mol) in 25 ml of solution shows a temperature rise of 0.03°C for complete oxygenation. Each mole of haemoglobin binds 4 moles of oxygen. If the heat capacity of the solution is 4.2 J/K-ml, the amount of heat released per mole of oxygen bound (in kJ) is

TestHub · Accepted Answer

The heat released, q, is calculated as:

q = 4.2 × 25 × 0.03 = 3.15 J

The moles of hemoglobin are:

Moles of hemoglobin = 6.3/64000 = 9.84 × 10^-5 mol

Since four moles of O_₂ bind per mole of hemoglobin, the moles of O_₂ bound are:

Moles of O₂ bound = 4 × 9.84 × 10^-5 = 3.94 × 10^-4 mol

The heat released per mole of O_₂ is:

Heat per mole of O₂ = 3.15/(3.94 × 10^-4) = 8000 J = 8 kJ

The answer is 8.

Chemistry - Thermochemistry Question with Solution | TestHub

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