"Strike anywhere" matches contain P4S3, a compound that ignites when heated by friction. It reacts vigorously with oxygen, as follows: P4S3(s) + 8O2(g) → P4O10(s) + 3SO2(g) ∆H°reaction = -3,677 kJ Use data from the hint to determine ∆H°f for P4S3(s). 25 In some liquid-fuel rockets
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.
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"Strike anywhere" matches contain P4S3, a compound that ignites when heated by friction. It reacts vigorously with oxygen, as follows:
P4S3(s) + 8O2(g) → P4O10(s) + 3SO2(g)
∆H°reaction = -3,677 kJ
In some liquid-fuel rockets, such as the lunar lander module of the Apollo Moon missions, the fuels are liquid hydrazine (N2H4) and dinitrogen tetroxide gas (N2O4). The two chemicals ignite on contact to release very large amounts of energy:
2N2H4(l) + N2O4(g) → 3N2(g) + 4H2O(g)
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