2MnO2(s)-->2MnO(s)+O2(g) H1 = +272.0 kJ/mol -----(1)
MnO2(s)+Mn(s)-->2MnO(s) H2=-248.9 kJ/mol ---- (2)
standard enthalpy of formation of manganese(ll)oxide, MnO(s) is
Mn(s) + (1/2) O2 (g) ----> MnO(s) : H = ? ------(3)
Eqn(3) can be obtained from (1) & (2) as follows :
Eqn(3) = [(1/2)x reverse of Eqn(1)] + Eqn(2)
H = [(1/2)x(-H1 )] + H2
= [ (1/2)x(-272.0) ] + (-248.9)
= -384.9 kJ/mol
Therefore option (C) is correct
using Hess's law what is the standard enthalpy of formation of manganese(ll)oxide, MnO(s)? 2MnO2(s)-->2MnO(s)+O2(g) rxn= +272.0...
12) Use the following data to calculate the standard heat (enthalpy) of formation, ???, of manganese(IV) oxide, MnO2 (s). 2MnO2(s)--2MnO(s) + O2(g) MnO2(s) + Mn(s)- 2Mn0(s) ??-264 kJ ?? -240 kJ 13) Calculate the ??0nn for the following reaction. (Arf [SiO2(s)--910.9 kJ/mol; APf [SiCl4(g)]--657.0 kJ/mol; ??'f [HCI(g)1--92.3 kJ/mol; ? Hof [H2O(g),- -241.8 kJ/mol) SiO2(s) + 4HCI(g)-SiCI(g) + 2H2O(g)
Question 9 (1 point) Use the following equations to calculate the molar enthalpy of formation for manganese(IV) oxide, MnO2(s). MnO2(s) --> MnO(s) + 1/2O2(g) AH1 = 132 kJ/mol MnO2(s) + Mn(s) --> 2MnO(s) AH2 = -240 kJ/mol O +504 kJ/mol 0-504 kJ/mol 0-24.0 kJ/mol +24.0 kJ/mol 0-372 kJ/mol
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4. Using Hess's Law, calculate the enthalpy of formation of potassium chlorate: K (s) + Cl2 (g) + 3/2 02 (g) →KCIO: (s) AH = ? kJ Based on the enthalpy changes for the following reactions: 2 K (8) + Cl2 (g) → 2 KCI (3) AH - 874.0 kJ KCIO: (s) + 3 Mg (8) ► KCl (s) + 3 Mg0 (8) AHxx. - 1852.0 kJ MgO (3) ► Mg (s) + O2(g) AHan = +602.0 kJ
Using Hess's Law, determine the enthalpy change of the following reaction. CS2(1) + 3 O2(g) --> CO2(g) + 2 SO2(g) C(s) + O2(g) --> CO2(g) AH = -393.5 kJ/mol S(s) + O2(g) --> SO2(g) AH = -296.8 kJ/mol C(s) + 25(s) --> CS2(8) AH = +87.9 kJ/mol -899.2 kJ O-778.2 kJ -602.4 kJ - 1075.0 kJ
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