9-11 Flashcards
Pressure (P)
The force per unit area measured in SI units of pascals
Atmospheric pressure
The force per unit area exerted by air on all objects, measured in kilopascals (kPa)
Standard pressure (at sea level)
Average pressure is 101 kPa, is equal to 1 standard atmosphere (1 atm)
Standard Temperature and Pressure (STP)
0 degrees Celsius and 1 atm (101.325 kPa), standard conditions for working with gases (not convenient)
Standard Ambient Pressure (SATP)
Defined at 25 degrees Celsius and 100 kPa, this standard is much closer to laboratory conditions (more convenient)
SI and Non-SI Units of Gas Pressure
Pascal (SI unit) =1 Pa=1N/m^2
Atmosphere=1 atm= 101.325 kPa
Millimetres of mercury= 760mmHg=1 atm= 101.325kPa
Torricelli= 1 torr= 1 mm Hg
Relationship between Pressure and Volume
Inverse variation between pressure and volume of a gas, as pressure increases the volume decreases
Boyles Law Equation
P1V1 = P2V2
When temperature and amount of gas are held constant
Boyle’s Law States
As the pressure on a gas increases, the volume of the gas decreases proportionally provided that the temperature and chemical amount of gas remains constant
Absolute Zero
If using the Celsius scale, crosses x axis at -273 degrees Celsius. It is the lowest possible temperature
Absolute (kelvin) Temperature Scale
Absolute zero is the basis for this temperature scale
(-273 Celsius) = (0K)
Convert Celsius to kelvin = + 273
Convert kelvin to Celsius= - 273
Kelvin Scale STP and SATP
STP: 273.15 K and 101.325 kPa
SATP: 298.15 K and 100 kPa
Charles Law Equation
V1/T1 = V2/T2
Valid when pressure and amount of gas are held constant
Relationship between temperature and volume
As temperature increases the volume increases
Charles Law states that
As the temperature of a gas increases, the volume increases proportionally provided that the pressure and chemical amount of gas remains constant