Question

Write a balanced equation for (a) the combustion (reaction with oxygen gas) of glucose, \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\), to give carbon dioxide and water. (b) the reaction between xenon tetrafluoride gas and water to give xenon, oxygen, and hydrogen fluoride gases. (c) the reaction between aluminum and iron(III) oxide to give aluminum oxide and iron. (d) the formation of ammonia gas from its elements. (e) the reaction between sodium chloride, sulfur dioxide gas, steam, and oxygen to give sodium sulfate and hydrogen chloride gas.

Short answer

Question: Write the balanced chemical equations for the following reactions: a) The combustion of glucose b) The reaction of xenon tetrafluoride gas with water c) The reaction between aluminum and iron(III) oxide d) The formation of ammonia gas from its elements e) The reaction of sodium chloride, sulfur dioxide gas, steam, and oxygen Answer: a) C6H12O6 + 6 O2 → 6 CO2 + 6 H2O b) XeF4 + 2 H2O → Xe + O2 + 4 HF c) 2 Al + Fe2O3 → Al2O3 + 2 Fe d) N2 + 3 H2 → 2 NH3 e) 2 NaCl + SO2 + 2 H2O + O2 → Na2SO4 + 2 HCl

Step-by-step solution

Identification of reactants and products

For the combustion of glucose, the reactants are glucose (\(\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6}\)) and oxygen gas (\(\mathrm{O}_{2}\)). Combustion reactions give carbon dioxide (\(\mathrm{CO}_{2}\)) and water (\(\mathrm{H}_{2}\mathrm{O}\)) as the products.

Balancing the chemical equation

To balance the chemical equation, we start by balancing the carbon atoms, followed by hydrogen atoms, and finally oxygen atoms. The balanced equation for the combustion of glucose is: $$\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6} + 6\ \mathrm{O}_{2} \rightarrow 6\ \mathrm{CO}_{2} + 6\ \mathrm{H}_{2}\mathrm{O}$$ #b)

Identification of reactants and products

The reaction between xenon tetrafluoride gas (\(\mathrm{XeF}_{4}\)) and water (\(\mathrm{H}_{2}\mathrm{O}\)) gives xenon (\(\mathrm{Xe}\)), oxygen (\(\mathrm{O}_{2}\)), and hydrogen fluoride gases (\(\mathrm{HF}\)).

Balancing the chemical equation

To balance the chemical equation, we start by balancing the hydrogen atoms, followed by the oxygen atoms, and finally fluorine atoms. The balanced equation for this reaction is: $$\mathrm{XeF}_{4} + 2\ \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{Xe} + \mathrm{O}_{2} + 4\ \mathrm{HF}$$ #c)

Identification of reactants and products

The reaction between aluminum (\(\mathrm{Al}\)) and iron(III) oxide (\(\mathrm{Fe}_{2}\mathrm{O}_{3}\)) gives aluminum oxide (\(\mathrm{Al}_{2}\mathrm{O}_{3}\)) and iron (\(\mathrm{Fe}\)).

Balancing the chemical equation

To balance the chemical equation, we start by balancing the oxygen atoms, followed by the aluminum and iron atoms. The balanced equation for this reaction is: $$2\ \mathrm{Al} + \mathrm{Fe}_{2}\mathrm{O}_{3} \rightarrow \mathrm{Al}_{2}\mathrm{O}_{3} + 2\ \mathrm{Fe}$$ #d)

Identification of reactants and products

The formation of ammonia gas (\(\mathrm{NH}_{3}\)) from its elements involves nitrogen (\(\mathrm{N}_{2}\)) and hydrogen (\(\mathrm{H}_{2}\)) gases.

Balancing the chemical equation

To balance the chemical equation, we balance the nitrogen atoms followed by the hydrogen atoms. The balanced equation for the formation of ammonia is: $$\mathrm{N}_{2} + 3\ \mathrm{H}_{2} \rightarrow 2\ \mathrm{NH}_{3}$$ #e)

Identification of reactants and products

The reaction between sodium chloride (\(\mathrm{NaCl}\)), sulfur dioxide gas (\(\mathrm{SO}_{2}\)), steam (\(\mathrm{H}_{2}\mathrm{O}\)), and oxygen (\(\mathrm{O}_{2}\)) gives sodium sulfate (\(\mathrm{Na}_{2}\mathrm{SO}_{4}\)) and hydrogen chloride gas (\(\mathrm{HCl}\)).

Balancing the chemical equation

To balance the chemical equation, we start with sodium, followed by sulfur, chlorine, and finally oxygen & hydrogen. The balanced equation for this reaction is: $$2\ \mathrm{NaCl} + \mathrm{SO}_{2} + 2\ \mathrm{H}_{2}\mathrm{O} + \mathrm{O}_{2} \rightarrow \mathrm{Na}_{2}\mathrm{SO}_{4} + 2\ \mathrm{HCl}$$

Key concepts

Combustion Reactions

Combustion reactions happen when a substance reacts with oxygen, often releasing heat and light. One common example is the combustion of glucose \((\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6})\) in the presence of oxygen \((\mathrm{O}_2)\). This reaction creates carbon dioxide \((\mathrm{CO}_2)\) and water \((\mathrm{H}_2\mathrm{O})\).

Balanced chemical equations are important for describing these reactions accurately. To balance a combustion equation, start with the number of carbon atoms, then move to hydrogen, followed by oxygen atoms. For glucose, the balanced combustion equation is:

• \(\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6} + 6\ \mathrm{O}_{2} \rightarrow 6\ \mathrm{CO}_{2} + 6\ \mathrm{H}_{2}\mathrm{O}\).

This method ensures that mass is conserved across the reactants and products, meeting the law of conservation of mass.

Xenon Tetrafluoride Reactions

Xenon tetrafluoride \((\mathrm{XeF}_{4})\) is a compound that can react with water \((\mathrm{H}_{2}\mathrm{O})\). This reaction results in the production of xenon \((\mathrm{Xe})\), oxygen \((\mathrm{O}_{2})\), and hydrogen fluoride gases \((\mathrm{HF})\).

To balance this chemical reaction, one needs to first balance the hydrogen atoms, then move to oxygen, and lastly fluorine atoms. The balanced equation is:

• \(\mathrm{XeF}_{4} + 2\ \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{Xe} + \mathrm{O}_{2} + 4\ \mathrm{HF}\).

Balancing is key to ensuring that the count of each type of atom is the same on both sides of the equation. This process confirms that the reaction follows the law of conservation of mass.

Ammonia Formation

Ammonia \((\mathrm{NH}_{3})\) is commonly produced via combining nitrogen \((\mathrm{N}_{2})\) and hydrogen \((\mathrm{H}_{2})\) gases. This process is crucial in the industrial synthesis of ammonia known as the Haber process.

When writing the balanced chemical equation for ammonia formation, first balance the nitrogen atoms, followed by the hydrogen atoms. This results in the balanced equation:

• \(\mathrm{N}_{2} + 3\ \mathrm{H}_{2} \rightarrow 2\ \mathrm{NH}_{3}\).

Balancing these equations helps in understanding stoichiometric relationships, which are essential in predicting the yield of ammonia production. It also ensures compliance with the law of conservation of mass.

Thermite Reaction

The thermite reaction is a classic example of a redox (reduction-oxidation) reaction involving aluminum \((\mathrm{Al})\) and iron(III) oxide \((\mathrm{Fe}_{2}\mathrm{O}_{3})\). During this reaction, aluminum acts as a reducing agent and removes oxygen from iron oxide, forming aluminum oxide \((\mathrm{Al}_{2}\mathrm{O}_{3})\) and pure iron \((\mathrm{Fe})\).

To balance the thermite reaction, begin with the oxygen atoms, then balance the aluminum and iron atoms. The balanced chemical equation is:

• \(2\ \mathrm{Al} + \mathrm{Fe}_{2}\mathrm{O}_{3} \rightarrow \mathrm{Al}_{2}\mathrm{O}_{3} + 2\ \mathrm{Fe}\).

This reaction is highly exothermic, often used in welding iron, and demonstrates important principles of both energy change and mass balance in chemical reactions. Balancing helps maintain the proper proportions of reactants and products.