Chapter 1: The Properties of Gases

The Perfect Gas

•Gas: a form of matter that fills any container it occupies.

oIt is in continuous random motion.

oAverage speeds increase as the temperature is raised.

oExcept during collisions, the molecules of a gas are widely separated

from one another and move in paths that are largely unaffected by

intermolecular forces.

•Equation of State: p= f(T, V, n)

•Equation of State of a Perfect Gas: p= nRT/V

oPressure (p)= F/A to which theforce is applied F= mg, m= ρV,

where ρ is mass density.

The greater force acting on a given area, the greater the

pressure.

If two gases are in separate containers that share a common

movable wall, the gas that has the higher pressure will tend to

compress the gas that has lower pressure.

Mechanical Equilibrium: when the two pressures are equal and

the wall has no tendency to move (high pressure lowers and low

pressure increases).

Barometer: measures the pressure exerted by the atmosphere.

Hydrostatic Pressure (p)= ρgh, where g is gravity and h is the

height.

Bayard-Alpert Pressure Gauge: interpretation of pressure is

based on the ionization of molecules present in the gas and the

resulting current of ions.

Capacitance Manometer: the deflection of a diaphragm relative

to a fixed electrode is monitored through its effect on the

capacitance of arrangement.

oTemperature (T): the property that indicates the direction of the flow of

energy through a thermally conducting, rigid wall.

When energy flows from A to B when they are in contact, then

we say that A has a higher temperature than B (high temp will

flow towards low temp).

Diathermic Boundary: if a change of state is observed when two

objects at different temperatures are brought into contact

(metal container).

Adiabatic Boundary: if no change occurs even though the two

objects have different temperatures (vacuum flask).

Thermal Equilibrium: established if no change of state occurs

when two objects A to B are in contact through a diathermic

boundary.

Zeroth Law of Thermodynamics: if A is in thermal equilibrium

with B, and B is in thermal equilibrium with C, then C is also in

equilibrium with A.

Perfect-Gas Temperature Scale/ Thermodynamic Temperature

Scale: using the pressure of a gas and is independent of the

identity of the gas.

T/K= θ/°C + 273.15, where θ is the temperature of the Celsius

scale (implies that a difference in temperature of 1°C is

equivalent to a difference of 1K 25°C = 298.15K).

## Document Summary

The perfect gas: gas: a form of matter that fills any container it occupies. Equation of state of a perfect gas: p= nrt/v where r is mass density: pressure (p)= f/a to which theforce is applied f= mg, m= r v, The greater force acting on a given area, the greater the pressure. If two gases are in separate containers that share a common movable wall, the gas that has the higher pressure will tend to compress the gas that has lower pressure. Mechanical equilibrium: when the two pressures are equal and the wall has no tendency to move (high pressure lowers and low pressure increases). Barometer: measures the pressure exerted by the atmosphere. Hydrostatic pressure (p)= r gh, where g is gravity and h is the. Bayard-alpert pressure gauge: interpretation of pressure is based on the ionization of molecules present in the gas and the resulting current of ions.