Problem 102
Question
Which of the following is the expected product of the reaction of \(\mathrm{Mg}(s)\) and \(\mathrm{N}_{2}(g)\) under heat? (i) \(\mathrm{Mg}_{3} \mathrm{~N}(s),(\mathbf{i i}) \mathrm{MgN}_{2}(s),\) (iii) \(\mathrm{Mg}_{3} \mathrm{~N}_{2}(s)\) (iv) \(\mathrm{Mg}(s)\) and \(\mathrm{N}_{2}(g)\) will not react with one another.
Step-by-Step Solution
Verified Answer
The expected product is \( \mathrm{Mg}_{3}\mathrm{~N}_{2}(s) \).
1Step 1: Recall the General Reaction Rules
When a metal reacts with a non-metal, they generally form an ionic compound. Magnesium (Mg) is a metal, and nitrogen (e_2) is a non-metal, so they will react to form an ionic product.
2Step 2: Write the Possible Reaction Equation
For the reaction of magnesium (d 6s) with nitrogen (e_2g), the typical product is magnesium nitride. The balanced reaction can generally be represented as:\[3 \mathrm{Mg}(s) + \mathrm{N}_{2}(g) \rightarrow \mathrm{Mg}_{3}\mathrm{~N}_{2}(s)\]
3Step 3: Identify the Correct Product Based on Stoichiometry
From the balanced reaction equation, we see that 3 moles of Mg react with 1 mole of e_2 to produce the compound d 3e_2 (s). Therefore, based on stoichiometry and expected reaction products, d 3e_2 is the expected product.
Key Concepts
Ionic CompoundsStoichiometryReaction EquationsMetal and Non-metal Reactions
Ionic Compounds
Ionic compounds are formed when metals react with non-metals. These compounds result from the complete transfer of electrons from a metal to a non-metal, creating ions. The metal loses electrons to become a positively charged ion, while the non-metal gains those electrons to become negatively charged.
\( \text{Mg} \) as a metal, loses electrons to become \( \text{Mg}^{2+} \) ions, while nitrogen as a non-metal gains electrons to form \( \text{N}^{3-} \) ions. The ions form a lattice structure in the compound due to these opposing charges, creating a stable ionic compound.
Key characteristics of ionic compounds include:
\( \text{Mg} \) as a metal, loses electrons to become \( \text{Mg}^{2+} \) ions, while nitrogen as a non-metal gains electrons to form \( \text{N}^{3-} \) ions. The ions form a lattice structure in the compound due to these opposing charges, creating a stable ionic compound.
Key characteristics of ionic compounds include:
- Form solid crystals at room temperature
- Have high melting and boiling points
- Conduct electricity when dissolved in water or molten
Stoichiometry
Stoichiometry refers to the calculation of reactants and products in chemical reactions. It allows us to predict the amounts of substances consumed and formed in a reaction. In practice, stoichiometry is used to balance chemical equations to reflect the law of conservation of mass.
For the reaction of magnesium with nitrogen, the balanced chemical equation is:\[3 \text{Mg}(s) + \text{N}_2(g) \rightarrow \text{Mg}_3\text{N}_2(s)\]This equation shows that three moles of magnesium react with one mole of nitrogen to produce one mole of magnesium nitride.
It illustrates the stoichiometry of this reaction as you account for all atoms in the reactants matching those in the products. Balancing chemical equations ensures that the reaction complies with the conservation of atoms in a chemical process.
For the reaction of magnesium with nitrogen, the balanced chemical equation is:\[3 \text{Mg}(s) + \text{N}_2(g) \rightarrow \text{Mg}_3\text{N}_2(s)\]This equation shows that three moles of magnesium react with one mole of nitrogen to produce one mole of magnesium nitride.
It illustrates the stoichiometry of this reaction as you account for all atoms in the reactants matching those in the products. Balancing chemical equations ensures that the reaction complies with the conservation of atoms in a chemical process.
Reaction Equations
A reaction equation represents a chemical reaction using chemical formulas and symbols. It shows which reactants transform into which products. For an equation to be balanced, the number of atoms of each element on the reactant side must equal the number on the product side.
In our example, the reaction between magnesium and nitrogen is expressed as:\[3 \text{Mg}(s) + \text{N}_2(g) \rightarrow \text{Mg}_3\text{N}_2(s)\]Each element in the reactants matches those in the products, maintaining mass balance. This example highlights how symbols and numbers give quantitative and qualitative information about the substances involved in the reaction.
Balancing these equations involve altering coefficients before elements and compounds, not the chemical formula itself.
In our example, the reaction between magnesium and nitrogen is expressed as:\[3 \text{Mg}(s) + \text{N}_2(g) \rightarrow \text{Mg}_3\text{N}_2(s)\]Each element in the reactants matches those in the products, maintaining mass balance. This example highlights how symbols and numbers give quantitative and qualitative information about the substances involved in the reaction.
Balancing these equations involve altering coefficients before elements and compounds, not the chemical formula itself.
Metal and Non-metal Reactions
Reactions between metals and non-metals are quite common. These reactions often result in the formation of ionic compounds due to the transfer of electrons. Metal atoms tend to lose electrons while non-metal atoms gain electrons during these reactions.
Taking magnesium (a metal) and nitrogen (a non-metal) as an example, when they react, magnesium atoms lose electrons to form \( \text{Mg}^{2+} \) ions and nitrogen atoms gain electrons to form \( \text{N}^{3-} \) ions, leading to the formation of magnesium nitride \( \text{Mg}_3\text{N}_2 \).
Important points about such reactions include:
Taking magnesium (a metal) and nitrogen (a non-metal) as an example, when they react, magnesium atoms lose electrons to form \( \text{Mg}^{2+} \) ions and nitrogen atoms gain electrons to form \( \text{N}^{3-} \) ions, leading to the formation of magnesium nitride \( \text{Mg}_3\text{N}_2 \).
Important points about such reactions include:
- Metals tend to lose electrons easily
- Non-metals have high electron affinity
- Ionic compounds result from the electrostatic attraction between the ions
Other exercises in this chapter
Problem 99
Hydrogen is an unusual element because it behaves in some ways like the alkali metal elements and in other ways like nonmetals. Its properties can be explained
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(a) One of the alkali metals reacts with oxygen to form a solid white substance. When this substance is dissolved in water, the solution gives a positive test f
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