5.2 Pressure Flashcards
Define gas pressure
Gas pressure is the force per unit area that results from gas paticles colliding with the sufaces around them.
Pressure is measured in a number of units. Name them.
millimeter of mercury (mmHg)
torr - millimeter of mercury (torr)
pascal (Pa)
pounds per square inch (psi)
inches of mercury (in Hg)
atmosphere (atm)
What is a barometer, how does it work, what does it measure, and in what unit?
A barometer is an evaculated glass tube, the tip of which is submerged in a pool of mercury. The liquid is forced upward into the evaculated tube by atmospheric pressure on the liquid’s surface. The mercury column rises with increasing armospheric pressure or falls decreasing atmospheric pressure. The unit of measure is millimeter of mercury.
What is a pascal?
The SI unit of pressure, pascal (Pa), defined as 1 newton (N) per square meter.
1 Pa = 1 N / m^2
What is the pressure unit, atmosphere?
The unit of pressure, atmosphere (atm), is the average pressure at sea level.
1 atm = 760 mmHg
What is a torr?
A torr is another name for millimeter of mercury, named after the Italian physicist Evangelista Torricelli. A torr is a mmHg.
1 torr = 1 mmHg
What are “inches of mercury”?
The unit of measure, inches of mercury (in Hg), measures in the same fashion as millimeters of mercury (mmHg) only converted into inches.
29.92 in Hg = 1 atm
760 mmHg = 1 atm
What is psi?
Psi is a common unit of measurement for pressure in pounds per square inch.
14.7 psi = 1 atm
Describe the effect of pressure imbalance, in regard to one’s ears.
The pain you fell in your ears upon ascending a mountain is caused by a pressure imbalance berween the cavities in your ears and the outside air.
What is pressure?
Pressure is force exerted per unit area by gas particles (molecules or atoms) as they strike the surface around them.
