For which of the following reactions is A, H° equal to Af H° of the product(s)? You do not need to look up any values to answer this question. Check all that apply. • View Available Hint(s) O Li(s) + ÷F2(1)→LIF(s) O C(s) + O2(9)→CO2(9) O CO(9) + O2(9)→CO2(9) O 2Li(s) + F2(9)→2LİF(s) o Li(s) + ÷F2(9)→LIF(s) O BaCO3 (8)→BaO(s) + CO2(9) The combustion of pentane, C3H12, occurs via the reaction CH12(9) + 802 (9)→5CO2(9) + 6H2O(9) with heat of formation values given by the following table: Substance |(kJ mol-1)| C;H12 (9) -119.9 CO2(9) -393.5 H2O(g) -241.8 Calculate the enthalpy for the combustion of pentane. Express your answer to four significant figures and include the appropriate units. • View Available Hint(s) HA ? A;H° = Value Units Submit
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 AS THEY ARE BOTH MARKED TOGETHER but they are different questions. I will also consider giving you thumbs up for help.
![For which of the following reactions is Ar H° equal to Af H° of the product(s)?
The standard heat of formation, Af H°, is defined as the enthalpy change for the
formation of one mole of substance from its constituent elements in their standard
You do not need to look up any values to answer this question.
states. Thus, elements in their standard states have Af H° = 0. Heat of
formation values can be used to calculate the enthalpy change of any reaction.
Check all that apply.
• View Available Hint(s)
Consider, for example, the reaction
2NO(9) + O2(9)
2ΝΟ (9)
O Li(s) + ¿F2(1)–→LİF(s)
with heat of formation values given by the following table:
O C(s) + O2(9)→CO2(9)
Af H°
(kJ mol-1)
Substance
O CO(9) + 02(9)→CO2(9)
NO(9)
90.2
O2 (9)
O 2Li(s) + F2 (9)–→2LİF(s)
NO2(9)
Li(s) + F2(9)→LİF(s)
33.2
O BaCO3 (s)→BaO(s) + CO2(9)
Then the heat of formation for the overall reaction is
Δ.ΗΣη, Δ Η (products ) -ΣΤ, Δ Η' (reactants)
2(33.2)
[2(90.2) + 0]
-114 kJ mol-1
=
The combustion of pentane, C5 H12, occurs via the reaction
C5H12(9) + 802(9)→5CO2(9)+ 6H2O(9)
with heat of formation values given by the following table:
Af H°
(kJ mol-1)
Substance
C5H12 (9)
-119.9
CO2 (9)
-393.5
H2O(g)
-241.8
Calculate the enthalpy for the combustion of pentane.
Express your answer to four significant figures and include the appropriate units.
• View Available Hint(s)
?
A;H° =
Value
Units
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