1.) Using standard heats of formation, calculate the standard enthalpy change for the following reaction. C(s,graphite) + O2(g)CO2(g) ANSWER: __________ kJ
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.
1.) Using standard heats of formation, calculate the standard enthalpy change for the following reaction.
C(s,graphite) + O2(g)CO2(g)
ANSWER: __________ kJ
2.) Using standard heats of formation, calculate the standard enthalpy change for the following reaction.
CaCO3(s)CaO(s) + CO2(g)
ANSWER: ___________ kJ
3.) A scientist measures the standard enthalpy change for the following reaction to be 214.3 kJ :
CH4(g) + H2O(g)3H2(g) + CO(g)
Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of H2O(g) is _________ kJ/mol.
4.) A scientist measures the standard enthalpy change for the following reaction to be 209.8 kJ :
CH4(g) + H2O(g)3H2(g) + CO(g)
Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of CH4(g) is _________ kJ/mol.
5.) The following thermochemical equation is for the reaction of iron(III) oxide(s) with hydrogen(g) to form iron(s) and water(g).
Fe2O3(s) + 3H2(g)2Fe(s) + 3H2O(g) H = 98.8 kJ
When 61.3 grams of iron(III) oxide(s) react with excess hydrogen(g), kJ of energy are _________ evolved or absorbed?
6.) The following thermochemical equation is for the reaction of sodium(s) with water(l) to form sodium hydroxide(aq) and hydrogen(g).
2Na(s) + 2H2O(l)2NaOH(aq) + H2(g) H = -369 kJ
When 7.13 grams of sodium(s) react with excess water(l), kJ of energy are _________ evolved or absorbed?
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