Consider the following reaction: 2 Mg + O2 → 2 MgO △H rxn = -1203 kJ
Calculate the amount of heat (in kJ) associated with complete reaction of 4 moles of Mg.
To calculate the amount of heat associated with the complete reaction of 4 moles of Mg, you need to use the given ΔHrxn value of -1203 kJ and the stoichiometry of the reaction.
The stoichiometry of the reaction indicates that 2 moles of Mg react to form 2 moles of MgO, with the release of -1203 kJ of heat.
We can set up a proportion to find the amount of heat released when 4 moles of Mg react:
2 moles of Mg : -1203 kJ
4 moles of Mg : x (kJ)
Using the proportion, we can solve for x:
(4 moles of Mg) / (2 moles of Mg) = x kJ / (-1203 kJ)
Simplifying the equation, we get:
4/2 = x / -1203
2 = x / -1203
Multiply both sides by -1203 to solve for x:
2 * (-1203) = x
x = -2406 kJ
Therefore, the amount of heat associated with the complete reaction of 4 moles of Mg is -2406 kJ. Note that the negative sign indicates the release of heat in the reaction.