Gas expansion Definition and 69 Threads

Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. As energy in particles increases, they start moving faster and faster weakening the intermolecular forces between them, therefore expanding the substance.

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  1. C

    How Does Gas Volume Change After Combustion in an Engine?

    Hi you all Seaching in internet, I have not found an answer to this: In a air-gasoline stechiometric mixture, what can be the volumen relationship between the unburned (intake gas) and final exhaust gases?. I guess temperature is important, but let's consider a normal working...
  2. G

    High altitude balloon gas expansion

    Homework Statement Could someone help me calculate the rate of expansion of gas (helium or hydrogen) in a balloon at different altitudes. temperature is -30f at all altitudes http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html <- chart for air pressure Homework...
  3. E

    Solving Gas Expansion in Equal Containers

    Homework Statement The problem states: Two small containers of equal volume, 100 cm^3, each contain helium gas at 0 degrees C and 1.00 atm pressure. The two containers are joined by a small open tube of negligible volume, allowing gas to flow from one container to the other. What common...
  4. J

    Stuck with a gas expansion problem?

    Hi, i think I've got the first part of this question done but I am stuck with the rest, so i'll post the lot in case you think i have the first part wrong. a) Derive and expression for the work done by an ideal gas when it expands isothermally at temperature T from a volume V1 to V2. b)...
  5. S

    First law of thermodynamics. Gas expansion

    1.1 kg off air with pressure 10^6 Pa, temperature 125 celciusdegrees, gets to expand until the volume is five times bigger than in the beginning. In every moment of the expansion, the amount of (warmth energy = Q) contributed is one fourth of the work done by the gas. 1 kmol of air weighs about...
  6. B

    Calculating Gas Expansion Ratio for Fireball Formation

    Hi All, How to work out the expansion ratio of a gas fireball. Eg: Just say we have a ball of gas-- no container, 1 liter in volume suspended in mid air & we ignite it, how far would the flame front extend to form the fireball, what volume would it occupy once ignited?. An example of...
  7. S

    Calculating Work for Monatomic Gas Expansion

    Homework Statement one mole of a monatomic gas expands from V_i = V_0 to V_f = 3V_0 according to the relationship: p = P_0[1 - 0.9sin( (pi(V - V_0))/4V_0 )] a) compute the work done by the gas as it expands from V_i = V_0 to V_f = 3V_0 b) compute the net heat flow during this expansion c)...
  8. R

    Gas Expansion and Temperature Change in PE Exam

    I have been working on a series of questions dealing with gas expansion and temperature change for my PE exam. \frac{}{}
  9. F

    Exploring Gas Expansion in High School Chemistry Class

    I am in high school chemistry and we are learning about gases. Do gases expand indefinitely? Or at least until the gas is evenly distributed throughout all the other gases that are present?
  10. E

    Easy thermo problem: gas expansion

    Homework Statement Imagine some helium in a cylinder with an initial volume of 1 liter and an initial pressure of 1 atm. Somehow the helium is made to expand to a final volume of 3 liters, in such a way that its pressure rises in direct proportion to its volume. (a) Sketch a graph of...
  11. S

    Does Gas Density Influence Expansion When Heated?

    Hi, Apart from heat and number of moles, what dictates how much a gas will expand when exposed to heat. Is it density? The density of Xenon is 5.894 g/L and the density of Helium is 0.1786 g/L does this mean that if they were both in the same conditions of volume of container, number of...
  12. S

    Speed of gas expansion & Size of expansion

    Hi, Ive a couple of questions. 1) Ideal gases expand according to temperature. But how quickly does it take for it to expand to its destined size? Lets say if I had 100 moles of Argon and heated it to 373kelvins. How long would it take for it to expand to it final size? 2) To what...
  13. C

    Preventing Gas Expansion: Molar Specific Heats at Constant Pressure & Volume

    Aren't we doing some work to prevent the gas from expanding if we maintain the constant volume. So shouldn't molar specific heat at constant pressure be equal to constant volume?
  14. I

    Thermodynamics and Gas expansion

    Here's the Question: In a Classroom there are 50 rows of students. A container of N20 (laughing gas) was opened at the front row and tear gas (molar mass 240 gm/mole) was opened simultaneously at the rear of the room. Which row of students will be the first to be laughing with tears in their...
  15. T

    How Do You Calculate the Initial Pressure in an Air Rifle Using Thermodynamics?

    an air rifle shoots a lead pellet by allowing high pressure gas to expand. This happens quickly so it is an adiabatic process. initially 12 cubic centimeters of air are admitted to the barrel. It behaves as an ideal gas, \gamma = 1.40. The air expands behind a 1.1 g pellet and pushes on it as...
  16. P

    .Calculating Heat Released from Gas Expansion at Constant Temperature

    An ideal gas at pressure, volume, and temp, Po, Vo, and To, respectively, is heated to point A, allowed to expand to point B also at A's temperature 2To, and then returned to the original condition. The internal energy increases by 3PoVo/2 going from point B to point To. How much heat left the...
  17. A

    Calculating Work in Isothermal Gas Expansion with Variable R_v

    Calculate the work W done by the gas during the isothermal expansion (path C). It may be be convenient to generalize your results by using the variable R_v, which is the ratio of final to initial volumes (equal to 4 for the expansions shown in the figure.) Express W in terms of p_0, V_0, and...
  18. D

    How Quickly Does an Ideal Gas Expand with Temperature Change?

    can anyone give me an equation for the rate that an ideal gas expands in a temperature change. like when a gas goes from 30 degrees to 50 degrees in a baloon. how quickly would it expand?
  19. T

    Gas Expansion: Water Changing from Liquid to Solid

    I am doing a physics problem in my High School class and I cannot find the answer to this: How much does water expand when changing from a liquid to a solid. Is there a percent? Example, when a gallon of water fully evaporates how much space does the vapor take up? Thanks alot!
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