Concept explainers
Interpretation:
The standard enthalpies of formation of
Concept Introduction:
The change in enthalpy that is associated with the formation of one mole of a substance from its related elements being in standard state is called standard enthalpy of formation (
The standard enthalpy of reaction is the enthalpy of reaction that takes place under standard conditions.
The equation for determining the standard enthalpies of compound and element can be given by,
Answer to Problem 6.125QP
Standard enthalpy of formation of
Standard enthalpy of formation of
Change in enthalpy of formation of
Explanation of Solution
The chemical equations can be given,
Using the values of standard enthalpies of formation,
Standard enthalpy of formation of
Standard enthalpy of formation of Water =
The equations can be given as,
The equations are summed up to get the standard enthalpy of formation of
Therefore, standard enthalpy of formation of
Similarly, the equations are summed up to get the standard enthalpy of formation of
To calculate the change in enthalpy of formation of
The equation can be given as,
Change in enthalpy of formation of
The change in enthalpy of formation of
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Chapter 6 Solutions
Chemistry
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- A compound is 82.7% carbon and 17.3% hydrogen, and has a molar mass of approximately 60 g/mol. When 1.000 g of this compound burns in excess oxygen, the enthalpy change is 49.53 kJ. (a) What is the empirical formula of this compound? (b) What is the molecular formula of this compound? (c) What is the standard enthalpy of formation of this compound? (d) Two compounds that have this molecular formula appear in Appendix G. Which one was used in this exercise?arrow_forwardSalicylic acid, C7H6O3, is one of the starting materials in the manufacture of aspirin. When 1.00 g of salicylic acid burns in a bomb calorimeter, the temperature of the bomb and water goes from 23.11C to 28.91C. The calorimeter and water absorb 21.9 kJ of heat. How much heat is given off when one mole of salicylic acid burns?arrow_forwardThe combustion of 1.00 mol liquid methyl alcohol (CH3OH) in excess oxygen is exothermic, giving 727 kJ of heat. (a) Write the thermochemical equation for this reaction. (b) Calculate the enthalpy change that accompanies the burning 10.0 g methanol. (c) Compare this with the amount of heat produced by 10.0 g octane, C8H18, a component of gasoline (see Exercise 5.41).arrow_forward
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