GS_Gases Module Overview

Gases Module Overview

Introduction

Did you notice that the gas phase of matter was left out of the last module? This is because gases do not behave the same way as liquids, solids, or solutions. They are not affected my intermolecular attractions. In this module, you will learn why! You will also learn about the properties of gases and the math associated with this special group of matter.

Module Lessons Preview

• What properties are common to all gases?
• What is pressure?
• What is the difference between a barometer and a manometer?
• How are Boyle's, Charles', Gay-Lussacs, and the Combined Gas Laws used?
• What is the Ideal Gas Law and what deviations from it are seen in real gases?
• What is STP?
• What is Dalton's Law of Partial Pressure?
• What is Graham's Law of Effusion?
• What is the kinetic theory and how does it relate to the gas laws?
• How are the rates of diffusion in gases and liquids related?
• Why is a gas less soluble in aqueous solution with increasing temperature, while most solids are more soluble with increasing temperature?
• How is Henry's Law used?

Key Terms

1. Absolute Zero - 0 K. Nature's lowest temperature
2. Avogadro's Law - equal volumes of gases contain equal numbers of molecules when they are at identical temperatures and pressures
3. Barometer - an apparatus for measuring atmospheric pressure
4. Boyle's Law - the volume of a given mass of a gas is inversely proportional to its pressure if the temperature is kept constant.  V 1/P. Also known as the pressure-volume law
5. Charles' Law - the volume of a given mass of a gas is directly proportional to its Kelvin temperature if the pressure is kept constant. VP. Also known as the temperature-volume law
6. Closed-End Manometer - a manometer with the operating fluid (mercury) closed at one end to the atmosphere
7. Combined Gas Law - for a given mass of gas, the product of its pressure and volume divided by its Kelvin temperature is a constant. PV/T = a constant
8. Dalton's Law of Partial Pressure - the total pressure of a mixture of gases equals the sum of their partial pressures
9. Diffusion - the spontaneous intermingling of one substance with another
10. Effusion - the movement of a gas through a very tiny opening into a region of lower pressure
11. Gay-Lussac's Law - the pressure of a given mass of gas is directly proportional to its Kelvin temperature if the volume is kept constant. T. Also known as the pressure-temperature law
12. Graham's Law - the rates of effusion of gases are inversely proportional to the square roots of their densities when compared at identical pressures and temperatures: effusion rate (constant P, T)
13. Henry's Law - also know as pressure-solubility law, the concentration of a gas dissolved in a liquid at any given temperature is directly proportional to the partial pressure of this gas above the solution
14. Ideal Gas - a hypothetical gas that obeys the gas laws exactly
15. Ideal Gas Law - PV=nRT, also known as the equation of state for an ideal gas
16. Kinetic Molecular Theory - a set of postulates used to explain the gas laws. A gas consists of an extremely large number of very tiny, very hard particles in constant, random motion. They have negligible volume and k between collisions, experience no forces between themselves
17. Law of Combining - in reaction of gases, the numbers of moles and the volumes are in the same ratio (when all are the same T and P)
18. Manometer - a device for measuring the pressure within a closed system
19. Mole Fraction - the ratio of the number of moles of one components of a mixture to the total number of moles of all components
20. Mole Percent - the mole fraction of component expressed as a percentage
21. Open-End Manometer  - a manometer with the operating fluid (mercury) exposed at one end to the atmosphere
22. Partial Pressure - the pressure contributed by an individual gas to the total pressure of a gas mixture
23. Pascal - the SI unit of pressure
24. Pressure - force per unit area
25. Real Gas - a gas that does not follow the postulates of the kinetic molecular theory
26. Standard Atmosphere - 101,325 Pa. The pressure that supports a column of mercury. 760 mm high at 0°C. Abbreviated atm
27. Standard Molar Volume - the volume of 1 mol of a gas under standard conditions of temperature and pressure 22.4/1383L
28. STP - standard conditions of temperature and pressure 273.15 K (0°C) and 1 atm (760 torr)
29. Torr - a unit of pressure equal to 1/760 atm. 1mm Hg
30. Universal Gas Constant - the ratio of PV to nT for gases, R = 0.0821 L atm mole-1 K-1
31. Vapor Pressure - the pressure exerted by the vapor above a liquid are in equilibrium with each other)

eTextbook Reminder

As you read these content pages, also read the corresponding content in your etextbook. Work the example problems in the text as you read to make sure that you understand. The etextbook sections will be listed with the corresponding content pages on your schedule.  

Stoichiometry Practice Problems

Before you begin, print the module practice problems found below.  You should complete a section of problems after covering that particular portion of the content. 

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