/*! 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 86 Using the ideal gas model, deter... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Using the ideal gas model, determine the sonic velocity in \(\mathrm{m} / \mathrm{s}\) of steam at \(600 \mathrm{~K}\) and 50 bar.

Short Answer

Expert verified
600 m/s

Step by step solution

01

- Identify the Formula

To determine the sonic velocity in an ideal gas, use the formula for the speed of sound: \[ v = \sqrt{\gamma \frac{R T}{M}} \] where \( \gamma \) is the adiabatic index (ratio of specific heats), \( R \) is the universal gas constant, \( T \) is the temperature in Kelvin, and \( M \) is the molar mass of the gas.
02

- Gather Values

For steam (water vapor), the necessary constants are: \( \gamma \approx 1.3 \), \( R = 8.314 \, \text{J} / (\text{mol} \, \text{K}) \), \( T = 600 \, \text{K} \), and the molar mass of water, \( M \approx 0.018 \text{kg}/\text{mol} \).
03

- Substitute Values into Formula

Substitute the known values into the sonic velocity formula: \[ v = \sqrt{1.3 \times \frac{8.314 \, \text{J} / (\text{mol} \, \text{K}) \times 600 \, \text{K}}{0.018 \, \text{kg}/\text{mol}}} \]
04

- Calculate the Result

Perform the calculation inside the square root first: \[ \frac{8.314 \, \text{J} / (\text{mol} \, \text{K}) \times 600 \, \text{K}}{0.018 \, \text{kg}/\text{mol}} = \frac{4988.4 \, \text{J}/\text{mol}}{0.018 \, \text{kg}/\text{mol}} = 277133.33 \, \text{J}/\text{kg} \] Now multiply by \( \gamma \) and take the square root: \[ v = \sqrt{1.3 \times 277133.33} = \sqrt{360273.33} \approx 600 \, \text{m}/\text{s} \]

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 fundamental equation in thermodynamics. It describes the behavior of ideal gases by relating pressure, volume, and temperature. The equation is written as:
\( PV = nRT \)
where:
- \( P \) is the pressure,
- \( V \) is the volume,
- \( n \) is the number of moles,
- \( R \) is the universal gas constant (8.314 J/(mol K)),
- \( T \) is the temperature in Kelvin.
An ideal gas adheres perfectly to this law. While real gases exhibit slight deviations under certain conditions, the Ideal Gas Law remains a useful approximation in many practical situations such as the one in this exercise.
speed of sound
The speed of sound in a medium is the speed at which sound waves travel through that medium. For an ideal gas, the speed of sound can be determined using the formula:
\( v = \sqrt{\gamma \frac{RT}{M}} \)
Here:
- \( v \) is the speed of sound,
- \( \gamma \) is the adiabatic index (ratio of specific heats),
- \( R \) is the universal gas constant,
- \( T \) is the temperature in Kelvin,
- \( M \) is the molar mass of the gas.
This relationship shows that the speed of sound in a gas increases with temperature and decreases with molar mass. The adiabatic index \( \gamma \) accounts for the specific heat properties of the gas and varies between different gases. For instance, in the given problem, for steam (water vapor), \( \gamma \approx 1.3 \).
thermodynamics calculations
Thermodynamics calculations involve various principles and formulas to determine properties like temperature, pressure, volume, and energy of a system in equilibrium. In this problem, we use the thermodynamic concept of the speed of sound in an ideal gas.
To perform these calculations:
1. Identify the appropriate formula. For the speed of sound, we use \( v = \sqrt{\gamma \frac{RT}{M}} \).
2. Gather necessary values, such as temperature, gas constant, molar mass, and adiabatic index.
3. Substitute these values into the formula.
4. Perform arithmetic operations, including multiplication, division, and taking the square root, to find the desired property.
In our example, substituting the values for steam properties and performing the calculations yields a result of approximately 600 m/s for the speed of sound at 600 K and 50 bar.
steam properties
Understanding steam properties is essential for many thermodynamic calculations and engineering applications. Steam (water vapor) behaves as an ideal gas under certain conditions and its properties vary with temperature and pressure. Key properties include:
- **Adiabatic index (\(\gamma\))**: For steam, it is approximately 1.3. This value influences the speed of sound and other thermodynamic properties.
- **Molar mass (M)**: The molar mass of water vapor is approximately 0.018 kg/mol.
- **Temperature (T)**: In our problem, it is given as 600 K.
These properties are critical for calculating various thermodynamic quantities, using formulas such as the ideal gas law and the speed of sound equation. By understanding the properties of steam, one can accurately model and predict its behavior in different scenarios, which is especially important in fields like mechanical and chemical engineering.

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

An air-standard dual cycle has a compression ratio of 15 , and compression begins at \(100 \mathrm{kPa}, 25^{\circ} \mathrm{C}\). The maximum pressure is \(7.5 \mathrm{MPa}\). The heat transferred to air at constant pressure is equal to that at constant volume. Estimate the cycle efficiency. For air, take \(c_{p}=1.005 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}\) and \(c_{v}=0.718 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}\)

In an air-standard Brayton cycle, air from the atmosphere at 1 bar, \(300 \mathrm{~K}\) is compressed to 6 bar, and the maximum cycle temperature is limited to \(1050 \mathrm{~K}\). The mass flow rate of air is \(4 \mathrm{~kg} / \mathrm{s}\). The turbine and the compressor have isentropic efficiencies of \(85 \%\) and \(88 \%\), respectively, take specific heat for air \(\left(c_{p}\right)\) to be \(1.005 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}\) and \(k=1.4\). Determine (a) thermal efficiency of the cycle. (b) back work ratio. (c) nower outnut in \(\mathrm{kW}\)

How do internal and external combustion engines differ?

An engine working on the air-standard Otto cycle is supplied with air at \(0.1 \mathrm{MPa}, 27^{\circ} \mathrm{C}\). The compression ratio is 8 . The heat supplied is \(1400 \mathrm{~kJ} / \mathrm{kg}\). Calculate the maximum pressure and temperature of the cycle, the cycle efficiency, and the mean effective pressure. For air, take \(c_{p}=1.005 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}, c_{v}=0.718\) \(\mathrm{kJ} / \mathrm{kg} \cdot \mathrm{K}\) and \(k=1.4\)

Air enters the diffuser of a ramjet engine at \(50 \mathrm{kPa}, 230 \mathrm{~K}\), with a velocity of \(2600 \mathrm{~km} / \mathrm{h}\) and decelerates to negligible velocity. On the basis of an air-standard analysis, the heat addition is \(1050 \mathrm{~kJ}\) per \(\mathrm{kg}\) of air passing through the engine. Air exits the nozzle at \(50 \mathrm{kPa}\). Determine (a) the pressure at the diffuser exit, in \(\mathrm{kPa}\). (b) the velocity at the nozzle exit, in \(\mathrm{m} / \mathrm{s}\). Neglect kinetic energy except at the diffuser inlet and the nozzle exit.

See all solutions

Recommended explanations on Physics 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.