Question

\(\mathrm{NO}_{x}\) is a generic term for the nitrogen oxides, \(\mathrm{NO}\) and \(\mathrm{NO}_{2}\) \(\mathrm{NO}_{x}\) gases are air pollutants that react to form smog and acid rain. In order to reduce \(\mathrm{NO}_{x}\) emission from vehicle, catalytic converters are installed in car exhausts to decompose NO and \(\mathrm{NO}_{2}\) respectively into \(\mathrm{N}_{2}\) and \(\mathrm{O}_{2}(\mathbf{a})\) Write the balanced chemical equations for the decomposition of \(\mathrm{NO}\) and \(\mathrm{NO}_{2}\) respectively. (b) If the car produces \(100 \mathrm{~g} \mathrm{NO}_{x}\) a day, with equal mole ratio of \(\mathrm{NO}\) and \(\mathrm{NO}_{2}\), how many grams of \(\mathrm{NO}\) and \(\mathrm{NO}_{2}\) are produced respectively?

Short answer

The balanced chemical equations for the decomposition of NO and NO₂ are: \[2NO \rightarrow N_{2} + O_{2}\] and \[2NO_{2} \rightarrow N_{2} + 2O_{2}\] The car produces \(39.5\mathrm{~g}\) of NO and \(60.5\mathrm{~g}\) of NO₂ daily.

Step-by-step solution

The balanced chemical equation for the decomposition of NO is: \[2NO \rightarrow N_{2} + O_{2}\] #a2. Write the decomposition equation for NO₂# To write the balanced chemical equation for the decomposition of NO₂, we need to make sure the number of atoms for each element is equal on both sides of the equation. NO₂ decomposes into N₂ and O₂.

The balanced chemical equation for the decomposition of NO₂ is: \[2NO_{2} \rightarrow N_{2} + 2O_{2}\] #b1. Calculate moles of NOₓ produced daily# To calculate the moles of NOₓ produced daily, we first need to find the molar mass of NOₓ. Since we know that equal mole ratio of NO and NO₂ is produced daily, we can calculate the average molar mass of NOₓ.

The molar mass of NO is \(30.01\mathrm{g/mol}\) (14.01 for N and 16.00 for O) and the molar mass of NO₂ is \(46.01\mathrm{g/mol}\) (14.01 for N and 32.00 for O₂). The average molar mass of NOₓ is: \[\frac{30.01 + 46.01 }{2} = 38.01\mathrm{g/mol}\] Now, we can find the moles of NOₓ produced daily: \[\frac{100\mathrm{~g}}{38.01\mathrm{g/mol}} = 2.63\mathrm{~mol}\] #b2. Calculate the grams of NO and NO₂ produced daily# Since we know the equal mole ratio of NO and NO₂, we can now find the grams of each produced daily.

Divide the moles of NOₓ by 2 to find the moles of NO and NO₂ produced daily: \[2.63\mathrm{~mol}/2 = 1.315\mathrm{~mol}\] Now, multiply the moles of NO and NO₂ by their respective molar masses to find the grams of each produced daily: \[1.315\mathrm{~mol} \times 30.01\mathrm{g/mol} = 39.5\mathrm{~g}\,NO\] \[1.315\mathrm{~mol} \times 46.01\mathrm{g/mol} = 60.5\mathrm{~g}\,NO_{2}\] Hence, the car produces \(39.5\mathrm{~g}\) of NO and \(60.5\mathrm{~g}\) of NO₂ daily.

Key concepts

Nitrogen Oxides

Nitrogen oxides, often denoted as \( \mathrm{NO}_x \), consist primarily of two compounds: nitrogen monoxide \( (\mathrm{NO}) \) and nitrogen dioxide \( (\mathrm{NO}_2) \). These compounds are significant because they contribute to environmental issues such as smog and acid rain, both of which have serious impacts on human health and the environment.

• \( \mathrm{NO} \) and \( \mathrm{NO}_2 \) are produced during combustion processes, like in vehicle engines.
• They interact with other compounds in the atmosphere, leading to the formation of harmful byproducts such as ozone in the lower atmosphere.
• Acid rain formed by these chemicals can lead to soil and water acidification, harming plants and aquatic systems.

Understanding the roles of nitrogen oxides in air pollution is essential for developing strategies to mitigate their release into the atmosphere.

Air Pollution

Air pollution is the presence of harmful substances in the air at levels that pose a health risk. Nitrogen oxides are a key contributor to air pollution, primarily through the formation of ground-level ozone and particulates. This type of pollution can have severe environmental and health impacts.

• Exposure to air pollution can lead to respiratory diseases, cardiovascular conditions, and exacerbate asthma.
• Long-term exposure can result in reduced lung function and even premature death.
• Environmentally, pollutants can lead to ecosystem imbalances by harming wildlife and damaging plant life.

Efforts to reduce air pollution focus on limiting emissions from industrial sources and vehicles, using technologies like catalytic converters.

Catalytic Converters

Catalytic converters are devices used in vehicle exhaust systems to reduce the emission of harmful gases, including nitrogen oxides. They serve an essential role in converting \( \mathrm{NO}_x \) into harmless nitrogen \( (\mathrm{N}_2) \) and oxygen \( (\mathrm{O}_2) \).

• They work by facilitating a chemical reaction that breaks down nitrogen oxides and other pollutants into less harmful components.
• The catalyst materials, often composed of platinum, palladium, and rhodium, help in the oxidizing or reducing reactions needed for conversion.
• By using catalytic converters, vehicles emit significantly fewer pollutants, thereby reducing their impact on air quality.

This technology is crucial for meeting environmental regulations and improving air quality near highways and in urban areas.

Balanced Chemical Equations

Balanced chemical equations are essential in chemistry as they ensure that the number of atoms of each element is conserved in a chemical reaction. For nitrogen oxides, these equations are crucial in understanding how these compounds are broken down.

• For the decomposition of \( \mathrm{NO} \), the balanced equation is: \[2\mathrm{NO} \rightarrow \mathrm{N}_2 + \mathrm{O}_2\]
• For \( \mathrm{NO}_2 \), its decomposition is represented by: \[2\mathrm{NO}_2 \rightarrow \mathrm{N}_2 + 2\mathrm{O}_2\]
• Balancing involves making sure that there are equal numbers of each type of atom on both sides of the equation.

This balance is fundamental to the study of chemistry because it represents how substances rearrange during reactions without creating or destroying matter.