Δ H rxn ° for the combustion of gaseous ethanol is to be calculated. Concept introduction: The heat of the reaction ( Δ H rxn ° ) is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. Δ H rxn ° is negative for exothermic reaction and Δ H rxn ° is positive for an endothermic reaction. The formula to calculate Δ H rxn ° of reaction is as follows: Δ H rxn ° = ∑ Δ H reactant bond broken ° + ∑ Δ H product bond formed ° Or, Δ H rxn ° = ∑ BE reactant bond broken − ∑ BE product bond formed The bond energy of reactants is positive and the bond energy of products is negative.
Δ H rxn ° for the combustion of gaseous ethanol is to be calculated. Concept introduction: The heat of the reaction ( Δ H rxn ° ) is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. Δ H rxn ° is negative for exothermic reaction and Δ H rxn ° is positive for an endothermic reaction. The formula to calculate Δ H rxn ° of reaction is as follows: Δ H rxn ° = ∑ Δ H reactant bond broken ° + ∑ Δ H product bond formed ° Or, Δ H rxn ° = ∑ BE reactant bond broken − ∑ BE product bond formed The bond energy of reactants is positive and the bond energy of products is negative.
Definition Definition Number that is expressed before molecules, ions, and atoms such that it balances out the number of components present on either section of the equation in a chemical reaction. Stoichiometric coefficients can be a fraction or a whole number and are useful in determining the mole ratio among the reactants and products. In any equalized chemical equation, the number of components on either side of the equation will be the same.
Chapter 10, Problem 10.75P
(a)
Interpretation Introduction
Interpretation:
ΔHrxn° for the combustion of gaseous ethanol is to be calculated.
Concept introduction:
The heat of the reaction (ΔHrxn°) is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. ΔHrxn° is negative for exothermic reaction and ΔHrxn° is positive for an endothermic reaction.
The formula to calculate ΔHrxn° of reaction is as follows:
ΔHrxn°=∑ΔHreactant bond broken°+∑ΔHproduct bond formed°
Or,
ΔHrxn°=∑BEreactant bond broken−∑BEproduct bond formed
The bond energy of reactants is positive and the bond energy of products is negative.
(b)
Interpretation Introduction
Interpretation:
The enthalpy of reaction for the combustion of liquid ethanol is to be calculated.
Concept introduction:
The heat of the reaction (ΔHrxn°) is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. ΔHrxn° is negative for exothermic reaction and ΔHrxn° is positive for an endothermic reaction.
A combustion reaction is that reaction in which reactant is reacted with molecular oxygen to form the product. Heat is released and the energy is produced in the reaction. Molecular oxygen is employed as an oxidizing agent in these reactions.
(c)
Interpretation Introduction
Interpretation:
The enthalpy of reaction for the combustion of liquid ethanol calculated from the bond energies and standard enthalpies of formation is to be compared.
Concept introduction:
The standard enthalpy of reaction is calculated by the summation of standard enthalpy of formation of the product minus the summation of standard enthalpy of formation of reactant at the standard conditions. The formula to calculate the standard enthalpy of reaction (ΔHrxn°) is as follows:
ΔHrxn°=∑mΔHf (products)°−∑nΔHf (reactants)°
Here, m and n are the stoichiometric coefficients of reactants and product in the balanced chemical equation.
(d)
Interpretation Introduction
Interpretation:
ΔHrxn° for the formation of gaseous ethanol from ethylene gas with water vapor is to be calculated.
Concept introduction:
The heat of the reaction (ΔHrxn°) is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. ΔHrxn° is negative for exothermic reaction and ΔHrxn° is positive for an endothermic reaction.
The formula to calculate ΔHrxn° of reaction is as follows:
ΔHrxn°=∑ΔHreactant bond broken°+∑ΔHproduct bond formed°
Or,
ΔHrxn°=∑BEreactant bond broken−∑BEproduct bond formed
The bond energy of reactants is positive and the bond energy of products is negative.
Lewis structure is generally considered as a simplified structure of any molecule or atom. Lewis structure for any atom or molecule depicts the valence electrons as dots around the element’s symbol present in the molecule along with the bonds that connect them. Every element tries to complete an octet except the hydrogen atom.
Every element in the Lewis structure tries to attain eight electrons in its valence shell by transfer or share of electrons. This rule is known as the octet rule.
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Calorimetry Concept, Examples and Thermochemistry | How to Pass Chemistry; Author: Melissa Maribel;https://www.youtube.com/watch?v=nSh29lUGj00;License: Standard YouTube License, CC-BY