/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 84 Ammonia gas is synthesized by co... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Ammonia gas is synthesized by combining hydrogen and nitrogen: $$ 3 \mathrm{H}_{2}(\mathrm{g})+\mathrm{N}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{NH}_{3}(\mathrm{g}) $$ (a) If you want to produce 562 g of \(\mathrm{NH}_{3}\), what volume of \(\mathrm{H}_{2}\) gas, at \(56^{\circ} \mathrm{C}\) and \(745 \mathrm{mm} \mathrm{Hg}\), is required? (b) To produce 562 g of \(\mathrm{NH}_{3},\) what volume of air (the source of \(\mathrm{N}_{2}\) ) is required if the air is introduced at \(29^{\circ} \mathrm{C}\) and \(745 \mathrm{mm}\) Hg? (Assume the air sample has \(\left.78.1 \text { mole } \% N_{2} .\right)\)

Short Answer

Expert verified
You need 1374.6 L of H2 and 534.4 L of air.

Step by step solution

01

Calculate moles of NH3

The molar mass of ammonia, \(\mathrm{NH}_3\), is \(14.01 + 3(1.008) = 17.034\) g/mol. Calculate the moles of \(\mathrm{NH}_3\) by using the mass given.\[\text{Moles of } \mathrm{NH}_3 = \frac{562 \text{ g}}{17.034 \text{ g/mol}} \approx 33.00 \text{ mol}\]
02

Use stoichiometry to find moles of H2

The balanced chemical equation shows that 2 moles of \(\mathrm{NH}_3\) are produced for every 3 moles of \(\mathrm{H}_2\). Using the moles of \(\mathrm{NH}_3\) calculated, we find moles of \(\mathrm{H}_2\).\[\text{Moles of } \mathrm{H}_2 = \frac{3 \text{ moles H}_2}{2 \text{ moles NH}_3} \times 33.00 \text{ moles NH}_3 = 49.5 \text{ moles H}_2\]
03

Determine volume of H2 gas

Apply the ideal gas law \(PV = nRT\) to find the volume of \(\mathrm{H}_2\) gas required. Given the pressure \(P = 745 \text{ mmHg} = 0.980 \text{ atm}\), \(T = 56^\circ C = 329 \text{ K}\) and \(n = 49.5\) moles.\[V = \frac{nRT}{P} = \frac{49.5 \times 0.0821 \times 329}{0.980}\]After solving, \(V \approx 1374.6\text{ L}\)
04

Calculate moles of N2 needed

Since 2 moles of \(\mathrm{NH}_3\) are produced from 1 mole of \(\mathrm{N}_2\), calculate moles of \(\mathrm{N}_2\) needed:\[\text{Moles of } \mathrm{N}_2 = \frac{1 \text{ moles N}_2}{2 \text{ moles NH}_3} \times 33.00 \text{ moles NH}_3 = 16.5 \text{ moles N}_2\]
05

Calculate volume of air for N2

Since air is composed of 78.1% \(\mathrm{N}_2\) by mole, divide the moles of \(\mathrm{N}_2\) by 0.781 to find total moles of air:\[\text{Total moles of air} = \frac{16.5}{0.781} \approx 21.13 \text{ moles air}\]Apply the ideal gas law assuming conditions \(P = 745 \text{ mmHg} = 0.980 \text{ atm}\), \(T = 29^\circ C = 302 \text{ K}\):\[V = \frac{21.13 \times 0.0821 \times 302}{0.980} \approx 534.4 \text{ L}\]

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Ideal Gas Law
The ideal gas law is a mathematical formula used to describe the behavior of gases. It's a crucial tool in chemistry for understanding how gases will react under different conditions. The formula for the ideal gas law is given by \(PV = nRT\). Let's break it down to understand it better:
  • \(P\) is the pressure of the gas, usually measured in atmospheres (atm) or millimeters of mercury (mmHg).
  • \(V\) is the volume the gas occupies, which is typically measured in liters (L).
  • \(n\) represents the number of moles of gas, which ties into how much gas you have.
  • \(R\) is the ideal gas constant, often approximated as 0.0821 L·atm/mol·K.
  • \(T\) is the temperature in Kelvin; remember to convert Celsius to Kelvin by adding 273.15 to the Celsius temperature.
The ideal gas law is essential when dealing with gases because it allows us to predict how a gas will respond when one of the conditions changes (like pressure or temperature). It is particularly helpful for combining gases in chemical reactions, such as the synthesis of ammonia, where we need to calculate the volume of hydrogen gas required to produce a certain amount of ammonia.
Chemical Reactions
Chemical reactions involve the transformation of reactants into products. In our exercise, we're looking at the synthesis of ammonia (\(\mathrm{NH}_3\)) from hydrogen (\(\mathrm{H}_2\)) and nitrogen (\(\mathrm{N}_2\)). The balanced chemical equation for this reaction is:\[3 \mathrm{H}_{2} (g) + \mathrm{N}_{2} (g) \rightarrow 2 \mathrm{NH}_{3} (g)\]This equation shows the stoichiometry of the reaction, meaning it illustrates the exact proportions in which the reactants combine to form the products.
  • The numbers in front of the chemical formulas, like the 3 in front of \(\mathrm{H}_2\), represent the moles of each component involved in the reaction.
  • It tells us that 3 moles of hydrogen gas react with 1 mole of nitrogen gas to produce 2 moles of ammonia gas.
Understanding the stoichiometry in a chemical reaction is fundamental for calculating how much of each reactant is needed or how much product will be formed. It's critical when performing laboratory experiments or industrial synthesis like producing ammonia for fertilizers.
Mole Calculations
Mole calculations are an integral part of stoichiometry in chemistry, helping us quantify the amount of substances involved in reactions. The mole is a standard unit in chemistry that measures the number of particles, typically atoms or molecules, in a sample.The steps to perform mole calculations usually involve:
  • Determining the molar mass of compounds by adding up the atomic masses of the elements found on the periodic table.
  • Using the formula \(\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}}\) to convert the mass of a substance into moles.
  • Applying stoichiometry for converting moles of reactants to moles of products, as indicated in the balanced chemical equation.
In our ammonia synthesis example, we calculated the moles of \(\mathrm{NH}_3\) produced from a given mass, and then used stoichiometry to find out how many moles of \(\mathrm{H}_2\) and \(\mathrm{N}_2\) were needed. This detailed process is crucial for ensuring that chemical reactions are carried out with the correct proportions, leading to efficient use of resources and minimizing waste.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A sample of \(\mathrm{CO}_{2}\) gas has a pressure of \(56.5 \mathrm{mm}\) Hg in a 125-mL. flask. The sample is transferred to a new flask, where it has a pressure of \(62.3 \mathrm{mm}\) Hg at the same temperature. What is the volume of the new flask?

Silane, \(\mathrm{SiH}_{4},\) reacts with \(\mathrm{O}_{2}\) to give silicon dioxide and water vapor: $$ \mathrm{SiH}_{4}(\mathrm{g})+2 \mathrm{O}_{2}(\mathrm{g}) \longrightarrow \mathrm{SiO}_{2}(\mathrm{s})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $$ If you mix \(\mathrm{SiH}_{4}\) with \(\mathrm{O}_{2}\) in the correct stoichiometric ratio, and if the total pressure of the mixture is \(120 \mathrm{mm} \mathrm{Hg}\), what are the partial pressures of \(\mathrm{SiH}_{4}\) and \(\mathrm{O}_{2} ?\) When the reactants have been completely consumed, what is the total pressure in the flask? (Assume T is constant.)

If equal masses of \(\mathrm{O}_{2}\) and \(\mathrm{N}_{2}\) are placed in separate containers of equal volume at the same temperature, which of the following statements is true? If false, tell why it is false. (a) The pressure in the flask containing \(\mathrm{N}_{2}\) is greater than that in the llask containing \(\mathbf{O}_{2}\) (b) There are more molecules in the flask containing \(\mathrm{O}_{2}\) than in the flask containing \(\mathbf{N}_{2}\)

Acetaldehyde is a common liquid compound that vaporizes readily. Determine the molar mass of acetaldehyde from the following data: Sample mass \(=0.107 \mathrm{g} \quad\) Volume of gas \(=125 \mathrm{mL}\) Temperature \(=0.0^{\circ} \mathrm{C} \quad\) Pressure \(=331 \mathrm{mm} \mathrm{Hg}\)

A steel cylinder holds \(1.50 \mathrm{g}\) of ethanol, \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\). What is the pressure of the ethanol vapor if the cylinder has a volume of \(251 \mathrm{cm}^{3}\) and the temperature is \(250^{\circ} \mathrm{C}\) ? (Assume all of the ethanol is in the vapor phase at this temperature. \()\)

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.