What Is the Entropic Energy Change When Magnesium Burns in Oxygen?

AI Thread Summary
The standard entropies of formation for magnesium, oxygen, and magnesium oxide are 32.7 J/mol K, 205.2 J/mol K, and 26.9 J/mol K, respectively. To calculate the entropic energy change when 25 grams of magnesium burns in excess oxygen at 25°C, first determine the number of moles of magnesium and the corresponding moles of oxygen needed. The entropy change can be calculated using the formula: entropy change = entropy of products - sum of entropy of reactants. The discussion also raises the question of whether the reaction leads to an increase or decrease in entropy within the system. The overall reaction and calculations will clarify the entropic changes involved.
explore88
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standard entropy of formation ??

Homework Statement



the standard entropy of formation of magnesium is 32.7 J/mol k , That of oxygen gases 205.2 J/mol k

at that magnesium oxide is 26.9 J/mol k .

A) What is the entropic energy change when 25 grams of magnesium are burned inexcess oxygen at 25 celsius ??

B) Does the burning of magnesium in oxygen lead to increase or decrease in entropy in the system ??

I hope the solution step by step ..

regards ^_^ ..

Homework Equations





The Attempt at a Solution

 
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first find the no. of moles of Mg you have.
that would combine with the same no. of moles of O to give the same no. of moles of MgO.

entropy change = entropy of form of products - sum of entropy of form of reactants
 


explore88 said:

Homework Statement



the standard entropy of formation of magnesium is 32.7 J/mol k , That of oxygen gases 205.2 J/mol k

at that magnesium oxide is 26.9 J/mol k .

A) What is the entropic energy change when 25 grams of magnesium are burned inexcess oxygen at 25 celsius ??

B) Does the burning of magnesium in oxygen lead to increase or decrease in entropy in the system ??

I hope the solution step by step ..

regards ^_^ ..

You should probably write down some reactions to help you visualize the problem.
 
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