Gases Flashcards

Flashcards about gases, pressure and how to measure pressure

Pressure

A force exerted by the substance per unit area on another substance.

Pressure of a gas

The force that the gas exerts on the walls of its container.

Air

A mixture of gases and the particles in air move in every direction, exerting pressure in all directions.

Atmospheric pressure or air pressure

Pressure exerted by air in all directions.

SI unit of pressure

Pascal (Pa)

Symbol for atmospheres

atm

Symbol for millimeters of mercury

mm Hg or torrs

Symbol for kilopascals

kPa

Standard Temperature and Pressure (STP)

0 degrees Celsius = 273K and 1 atmosphere of pressure.

Barometer

Device that measures atmospheric pressure.

Manometer

Device that measures gas pressure; measures the difference between two different points of pressure.

Barometer

A scientific instrument that is used to measure air pressure in a certain environment.

Manometer

Can be used to measure the pressure of a gas in a closed container; the (difference in) height between the liquid levels (h) is a measure of the pressure; mercury is usually used because of its large density.

Open-tube manometer

the difference in mercury levels in units of torr or mmHg; atmospheric pressure pushes on the mercury from one direction, and the gas in the container pushes from the other direction.