Answer:
The reaction is:
Mg + 2HCl → MgCl2 + H2
The heat of reaction (ΔHrxn) can be calculated using the equation:
ΔHrxn = (mass of Mg)(heat capacity of HCl)(change in temperature)
ΔHrxn = (2.00 g)(75.3 J/(mol ∙ °C))(9.2°C)
= 1390.56 J/mol
ΔHrxn = 1390.56 J/mol / 1000 J/kJ
= 1.39056 kJ/mol
ΔHrxn = -1.39056 kJ/mol
= -44.4 kJ/mol
Adding 2.00 g of Mg metal to 95.0 mL of 1.00 M HCl in a coffee-cup calorimeter leads to a temperature increase of 9.2°C
If the molar heat capacity of 1.00 M HCl is the same as that for water [cP = 75.3 J/(mol ∙ °C)], what is ΔHrxn?
The answer is -44.4 kJ/mole in the textbook but I don't know how they get it.
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