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When one mole of magnesium is burned, it forms magnesium oxide and releases 39.2 J of...

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rtarasco | Student | eNotes Newbie

Posted November 14, 2012 at 10:35 PM via web

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When one mole of magnesium is burned, it forms magnesium oxide and releases 39.2 J of energy. Describe this chemical reaction in four different ways.

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llltkl | College Teacher | Valedictorian

Posted November 15, 2012 at 12:10 PM (Answer #1)

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A chemical reaction can be described in several different ways. For the given reaction, different forms are:

1. When one mole of magnesium is burned, it forms magnesium oxide and releases 39.2 J of energy (chemical information in words).

2. One gram-atom metallic magnesium burns in air with bright flames to produce one mole of white magnesium oxide and 39.2 J heat energy (representation stating stoichiometry in moles).

3. When 24.3 g metallic magnesium is burned in presence of sufficient amount of oxygen, 40.3 g magnesium oxide and 39.2 heat energy is produced (chemical information in words, stating stoichiometry in grams).

4. Mg + ½ O2 -> MgO + 39.2 J (energy)

(Symbolic representation)

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