High School Videos

Randy Dorn plans to ask the Washington State Legislature to delay high school graduation requirements in math and science. Dorn is State Superintendent of Public Instruction. He announced his request in Seattle Thursday. KUOW's Phyllis Fletcher reports.

This is the most common type of Combined Gas Law problem in high school chemistry. A volume of gas is collected at some given pressure and temperature (usually C) and you are asked to "correct" that volume to what it would be at standard temperature and pressure.

Avogadro's Number (6.022 x 1023) is a very, very large number. This calculation attempts to give you a sense of the immense size of Avogadro's Number.

Wet gas means that the gas has been collected over water and, consequently, is saturated with water vapor. Dalton's Law of Partial Pressures is used to subtract out the pressure of the water vapor, allowing us to calculate the pressure of the dry gas. Only then can the Combined Gas Law be used.

A common Combined Gas Law problem will specify that the pressure and temperature change by some factor (double, cut in half, etc.) without specifying any numbers. How does one go about solving such a problem? This video explains how.