What us the standard measure of air pressure in pascals?
474374
Standard atmospheric pressure is 101 325 Pa = 101.325 kPa = 1013.25 hPa = 1013.25 mbar = 760 Torr. This definition is used for pneumatic fluid power (ISO R554), and in the aerospace (ISO 2533) and petroleum (ISO 5024) industries.
715600
Usually pascal's.  But it really would not matter because you are calculating a ratio in this instance and no matter what units are used for pressure the same ratio will be produced in this problem.
276916
Atmospheric pressure is the pressure above any area in the Earth's atmosphere caused by the weight of air. Standard atmospheric pressure (atm) is discussed in the next section.\n\nAir masses are affected by the general atmospheric pressure within the mass, creating areas of high pressure (anti-cyclones) and low pressure (depressions).\n\nAs elevation increases, fewer air molecules are above. Therefore, atmospheric pressure decreases with increasing altitude. The following relationship is a first-order approximation:\n\n, \nwhere P is the pressure in pascals and h the height in metres. This shows that the pressure at an altitude of 31 km is about 10(5-2) Pa = 1000 Pa, or 1% of that at sea level1.
247306
It is Celsius for the Metric System.\n\nFor SI, it is Kelvin.
966327
I agree; c) is the right choice.  The other units are used to measure:\n\na)  power ratio\nb)  pressure\nd)  pressure (again)
652894
the amount of pressure exerted on an object
35270
G is for guage, which uses ambient pressure as the reference point as opposed to PSIA, where A is Absolute, which uses an absolute vacuum as the reference point.
956075
The maximum "inches of vacuum" would be roughly equal to the barometric pressure outside, around 29.92 inches for a typical day (1 atmosphere here on Earth).  This would be, for example, how far the mercury would rise if you pull air out of the top of a tube whose lower end is in a pool of mercury.\n\nAnother way which is commonly used in science and engineering is to measure in "inches of mercury" or "mm of mercury" (torr).  In this case, you pull a near perfect vacuum inside the tube (by sealing the end, filling it with mercury and flipping it over) and see how high the mercury is when it stops draining out.  A perfect vacuum in this case would be zero inches.  It all depends on whether you're measuring the vacuum inside the tube or outside!
848891
In the field of chemistry, "STP" (standard temperature & pressure) means T = 0 deg.C (or 273 K), and P = 1 ATM = 101.3 KPa.  The statement you make, "Is it pressure at 0K or 298 K?" doesn't make sense, since in a particular problem, having standard temperature doesn't imply you have standard pressure, nor vice-versa.  In the handbooks, constants for gases are given which are accurate when both T & P are standard.  If one isn't, you have to use a gas law to find the correct value.  Oh, and here's something else, which you don't have to worry about, but I'll say it just to point out that standards aren't always standardized:  in industry, chemical engineers often work in the U.S. system of units, and many of the tables specify 60 deg.F as "standard temperature."\n\nI just noticed something...that definition of 1 Bar as "standard pressure."  Like one of the previous posters, I thought, "That's nuts!"  Then I started to wonder....and I found this:\n\nstandard pressure. (P° or Po)\nStandard pressure is a pressure of 1 bar. Before 1982, the standard pressure was 1 atm (1 atm = 1.01325 bar).\n\nhttp://antoine.frostburg.edu/chem/senese/101/thermo/glossary.shtml\n\nI had never heard of that!  I received my Chem.E degree in 1996, well after 1982.  In every class I took, standard pressure was 1 ATM.
544464
A hand held instrument called a velometer. It measures the pressure of the air against a tube and gives a digital readout. Feet per second, Meters per sec.
111676
Actually standard pressure at sea level is taken to be 14.7 lbs/in^2. \n\nLots of things are factors in air pressure: \n\nAltitude of observations \n\nHeight of air column\n\ndensity of air, depending on temperature, and gas constitutents (constituents usually fairly slowly varying, but temperature varies rapidly)\n\nStrength of gravitational field\n\nTidal forces (small but measurable)\n\nLocal topography (orographic effects)\n\nair motion (usually driven by density differences, which are usually connected with tempearture). \n\n\n\nProbably the biggest factors are temperature, and altitude.
1160713
Convert temperatures to absolute; add 273 and then use Charles'law.0.55atm /173 = x /473 so x = 0.55atm times 473/173 = 1.5 atm.   That's the new pressure.
987167
Atmospheric pressure and physics
1181392
It is of a pressure equal to 0.6 ­ 1.1 atmosphere (600 ­ 1100 g/cm 2 ) at sea level (8.5 lbs/sq in 15.6 lbs/sq in)
716268
PV = nRT\nn = PV/RT\n\nP = standard pressure(don't know which one you're picking)\nV = 2 L\nT = standard temp(again don't know which one you're picking)\nR = constant you can decide which one you want to use at\nhttp://en.wikipedia.org/wiki/Ideal_gas_constant
149710
AREA\n\nPressure (symbol: p) is the force per unit area acting on a surface in a direction perpendicular to that surface. Mathematically:    P=F/A\nwhere:\np is the pressure \nF is the normal force \nA is the area.
820723
Atmospheric pressure is the pressure at any point in the Earth's atmosphere.\n\nIn most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location. Similarly, as elevation increases there is less overlying atmospheric mass, so that pressure decreases with increasing elevation. A column of air 1 square inch in cross section, measured from sea level to the top of the atmosphere, would weigh approximately 14.7 lb. A 1 m² column of air would weigh about 100 kilonewtons.\n\nStandard atmosphere (symbol: atm) is a unit of pressure and is defined as being precisely equal to 101,325 Pa. This value is intended to represent the mean sea level pressure at the latitude of Paris, France, and as a practical matter, approximates the mean sea level pressure for many of the industrialized nations (those with latitudes similar to Paris). One standard atmosphere is standard pressure used for pneumatic fluid power (ISO R554), and in the aerospace (ISO 2533) and petroleum (ISO 5024) industries.\n\nIn 1982, the International Union of Pure and Applied Chemistry (IUPAC) recommended that for the purposes of specifying the physical properties of substances, “the standard pressure” should be defined as precisely 100 kPa (≈750.062 torr) rather than the 101.325 kPa value of “one standard atmosphere”.[1] This value is used as the standard pressure for the compressor and the pneumatic tool industries (ISO 2787).[2] (see also Standard temperature and pressure)\n\nIn the United States, compressed air flow is often measured in "standard cubic feet" per unit of time, where the "standard" means the equivalent quantity of air at standard temperature and pressure. However, this standard atmosphere is defined slightly differently: temperature = 68 °F (20 °C), air density = 0.075 lb/ft³ (1.20 kg/m³), altitude = sea level, and relative humidity = 0%. In the air conditioning industry, the standard is often temperature = 32 °F (0 °C) instead. For natural gas, the petroleum industry uses a standard temperature of 60 °F (15.6 °C).\n\nAtmospheric pressure is often measured with a mercury barometer, and a height of approximately 760 mm (30 inches) of mercury is often used to teach, make visible, and illustrate (and measure) atmospheric pressure. However, since mercury is not a substance that humans commonly come in contact with, water often provides a more intuitive way to conceptualize the amount of pressure in one atmosphere.\n\nOne atmosphere (101.325 kPa or 14.7 lbf/in²) is the amount of pressure that can lift water approximately 10.3 m (33.9 feet). Thus, a diver at a depth 10.3 meters under water in a fresh-water lake experiences a pressure of about 2 atmospheres (1 atm for the air and 1 atm for the water).\n\nIn terms of city water pressure, one atmosphere is approximately one-half to one-fifth the pressure of typical city water mains (i.e., water pressure is around 2 to 5 atmospheres).\n\nThe most common type of barometer used in homes is the aneroid barometer (Figure 3). Inside this instrument is a small, flexible metal capsule called an aneroid cell. In the construction of the device, a vacuum is created inside the capsule so that small changes in outside air pressure cause the capsule to expand or contract. The size of the aneroid cell is then calibrated and any change in its volume is transmitted by springs and levers to an indicating arm that points to the corresponding atmospheric pressure.