The reaction;
O(g) +O2(g)→O3(g), ΔH = sum of bond enthalpy of reactants-sum of food enthalpy of products.
ΔH = ( bond enthalpy of O(g)+bond enthalpy of O2 (g) - bond enthalpy of O3(g)
-107.2 kJ/mol = O+487.7kJ/mol =O+487.7 kJ/mol +487.7kJ/mol =594.9 kJ/mol
Bond enthalpy (BE) of O3(g) is equals to 2× bond enthalpy of O3(g) because, O3(g) has two types of bonds from its lewis structure (0-0=0).
∴2BE of O3(g) = 594.9kJ/mol
Average bond enthalpy = 594.9kJ/mol/2
=297.45kJ/mol
∴ Averange bond enthalpy of O3(g) is 297.45kJ/mol.
1/5 + 1/4 =1/x
4x + 5x = 20
9x = 20
x = 2.22 hours Answer
Answer:
CaF2
Explanation:
Calcium fluoride is a solid formed by the chemical combination of Calcium (Ca) and Fluorine (F). Two molecules of fluorine (F2) and one molecule of Calcium (Ca) are needed to form the Calcium Fluoride molecule.
An ionic bond is formed between the Calcium and Fluorine atoms i.e. electrons are transferred from calcium atoms to fluorine atoms. The calcium ion is a cation with formula; Ca2+ while fluorine is an anion with formula; F-. Hence, it takes two molecules of Fluorine ion (F-) to form a relatively stable and neutral molecule with 1 molecule of Calcium ion (Ca2+).
I believe the correct answer from the choices listed above is the second option. The pair of elements that is most likely to chemically combine and form ionic bonds would be <span>lithium and chlorine. Lithium is metal and chlorine is nonmetal which as a compound forms ionic bonds. Hope this answers the question.</span>
<span>Two scientists wrote a paper detailing their research and conclusions and submitted it to a scientific journal. Several months later, they received the paper back from the publisher with many comments attached from several fellow scientists. It is either that they revise their study or replicate the study. Most scientists would revisit their work and the findings they had from their research. Most probable if they were successful and the comments of the publisher and the co-scientists were positive they could replicate the study to validate its accountability.<span>
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