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5) The formation of magnesium oxide (MgO) is represented by …

Chemistry Questions
Short Answer
Step by Step Solution
Chemistry Questions

5) The formation of magnesium oxide (MgO) is represented by the equation: [tex]Mg_{(s)} + frac{1}{2} O_{2(g)} rightarrow MgO_{(s)} + 601.7 , text{kJ}[/tex]. a) Is this reaction endothermic or exothermic? b) If 0.321 moles of [tex]O_2[/tex] reacted, what is the amount of heat absorbed or released?

Short Answer

The reaction is identified as exothermic because it releases 601.7 kJ of energy. By understanding the stoichiometry, one can calculate that reacting 0.321 moles of O2 releases a total of 386.2914 kJ of heat.

Step-by-Step Solution

Step 1: Identify the Reaction Type

To classify whether the reaction is endothermic or exothermic, examine the energy change noted in the equation. In this reaction:

  • Mg + ( frac{1}{2} O_2 ) ‚ÄöUi MgO + 601.7 kJ

The fact that 601.7 kJ is listed as a product indicates that the reaction releases energy. Thus, it is categorized as an exothermic reaction.

Step 2: Understand the Stoichiometry

Next, understand the relationship between the reactants and products in terms of energy release. The balanced equation indicates that:

  • ( frac{1}{2} O_2 ) forms 1 mole of MgO releasing 601.7 kJ.
  • 1 mole of O_2 can produce 2 moles of MgO, thus releasing 2 ‚àöo 601.7 kJ.

This understanding of stoichiometry is crucial for calculating heat release when dealing with specific amounts of reactants.

Step 3: Calculate Total Heat Released

Finally, you can now calculate the total heat released when reacting a specific quantity of O_2. For 0.321 moles of O_2, use the formula:

  • Total heat released = 0.321 moles ‚àöo 2 ‚àöo 601.7 kJ/mole

This calculation yields a total heat release of 386.2914 kJ when 0.321 moles of O_2 react.

Related Concepts

Reaction Type

A classification of chemical reactions based on energy change, distinguishing between endothermic (absorbing energy) and exothermic (releasing energy)

Stoichiometry

The study of the quantitative relationships between the amounts of reactants and products in a chemical reaction, crucial for predicting energy changes

Total Heat Released

The calculated energy output from a chemical reaction based on the moles of reactants used, often expressed in kilojoules (kj).

Table Of Contents
  1. 5) The formation of magnesium oxide (MgO) is represented by the equation: [tex]Mg_{(s)} + frac{1}{2} O_{2(g)} rightarrow MgO_{(s)} + 601.7 , text{kJ}[/tex]. a) Is this reaction endothermic or exothermic? b) If 0.321 moles of [tex]O_2[/tex] reacted, what is the amount of heat absorbed or released?

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