a. In our experiment, we assumed that the heat flow in to and out of the walls of the calorimeter (qcal) is small in comparison to the total heat flow and so it could be neglected. If we assume that the heat capacity (Ccal) of the calorimeter is 12 J/K, does this neglected heat flow account for your calculated percent error in the value of ΔHf° for MgO? Show your new calculations to explain why or why not. (The calculated percent error value of ΔHf° is 4.12 kj/mol)
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
Please answer both questions:
a. In our experiment, we assumed that the heat flow in to and out of the walls of the calorimeter (qcal) is small in comparison to the total heat flow and so it could be neglected. If we assume that the heat capacity (Ccal) of the calorimeter is 12 J/K, does this neglected heat flow account for your calculated percent error in the value of ΔHf° for MgO? Show your new calculations to explain why or why not. (The calculated percent error value of ΔHf° is 4.12 kj/mol)
b. Magnesium oxide can react with carbon dioxide present in the air to form magnesium carbonate. If a student used a very old bottle of magnesium oxide and a substantial amount of what we thought was magnesium oxide had been converted to magnesium carbonate, what physical evidence (if any) might you have observed?
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