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Workshop: Gas Laws and Applications
1. Consider an ice cube made of 8 water molecules in an absolutely empty rectangular box. A) Draw a three-dimensional sketch of the ice cube in the box, illustrating the ice cube on a molecular level using spheres to represent the water molecules. B) Draw a new sketch showing the molecules after the ice melts to become liquid water. C) Draw a third sketch showing the contents of the box after the water is vigorously heated, turning it completely to steam.
2. What if the process were reversed; would your sketches be different?
3. Instead of a box, consider a flexible-walled rubber balloon.
a) What happens to the balloon volume as it is heated?
b) What happens to the volume as it is cooled?
c) Express this relationship as an algebraic equation.
d) What happens to the pressure of the air in the balloon when its volume is reduced by squeezing it?
e) What happens to the pressure when the volume is allowed to increase back to its original quantity?
f) Express this relationship as an algebraic equation.
A flexible-walled container (like a balloon) holds 1.75 L of helium gas.
g) What is the volume of the container when the absolute temperature is increased by a factor of 1.5 while the pressure remains constant?
h) What is the new volume if the pressure is doubled while the temperature is kept constant?
i) How is the volume affected when both of the changes given in parts (a) and (b) are done simultaneously?
4. Define an ideal gas.
a) How is it different from a real gas?
b) Under what conditions is a real gas closely approximated by an ideal gas?
This material is based upon work supported by the National Science Foundation under Grant Number 1246120