# Consider the following reaction: #2Mg(s) + O_2(g) -> 2MgO(s)#, #DeltaH = -1204kJ#. Is this reaction exothermic or endothermic? How do you calculate the amount of heat transferred when 2.4 grams of Mg(s) reacts at constant pressure?

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How many grams of MgO are produced during an enthalpy change of -96.0 kJ? How many kilojoules of heat are absorbed when 7.50 g of MgO(s) is decomposed into Mg(s) and #O_2(g)# at constant pressure?

How many grams of MgO are produced during an enthalpy change of -96.0 kJ? How many kilojoules of heat are absorbed when 7.50 g of MgO(s) is decomposed into Mg(s) and

##### 1 Answer

#### Answer:

This reaction as written is clearly

#### Explanation:

We has..............

To make the arithmetic a bit easier we could write........

I am CLEARLY free to do this because

And so we combust a

And thus for the given molar quantity of magnesium,

So, in effect, we have treated enthalpy as a stoichiometric product of the reaction (which indeed it is!). And if

And when

Finally, you have proposed that a given mass of