Chapter 10 Chemistry The Central Science

Pressure

the force applied to a unit area of surface

atmosphere

a distinctive but intangible quality surrounding a person or thing

Boyle's Law

The relationship between the pressure and volume of a gas at constant temperture; when volume increase, pressure decreases.

Charle's Law

the physical law that the volume of a fixed mass of gas held at a constant pressure varies directly with the absolute temperature

Avogadro's hypotheses

equal volumes of gases at the same temperature and pressure contain equal numbers of particles

Avogadro's Law

the law that states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules

ideal-gas equation

PV=nRT, PV=nRT, which represents the relationship among pressure, temperature, volume, and moles of a gas, is called the _______.

ideal gas

A hypothetical gas whose pressure, volume, and temperature behavior is completely described by the ideal-gas equation.

gas constant

(physics) the universal constant in the gas equation: pressure times volume = R times temperature

standard temperature and pressure (STP)

273K and 1 atm, standard conditions for a gas at 0 degrees C and 1 atm

partial pressures

a portion of the total pressure of the mixture (what the individual gas would exert itself)

Dalton's law of partial pressures

states that the total pressure of a mixture of gases is equal to the sum of the pressures of all the gases in the mixture

mole fraction

The ratio of the moles of solute in solution to the total number of moles of both solvent and solute

Kinetic-molecular theory

the theory that all matter is composed of particles (atoms and molecules) moving constantly in random directions, describes the behavior of matter in terms of particles in motion

root mean-square (rms) speed

a type of average molecular speed, equal to the speed of a molecule having the average molecular kinetic energy; sqrt(3RT/Mm), where Mm = molar mass, The square root of the average of the squared speeds of the gas molecules in a gas sample.

effusion

the passage of a gas under pressure through a tiny opening, escape of a gas through an orifice or hole

Graham's Law

Law stating that the rate at which two different gases effuse/diffuse is inversely proportional to the square root of their molecular weight: R₁/R₂ = (MM₂/MM₁)^(1/2).

diffusion

process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated, spreading of one substance through a space occupied by one or more other substances

mean free path

the average distance traveled by a molecule between collisions (is short)

van der Waals equation

is an equation of state for gases that modifies the ideal-gas equation to account for intrinsic molecular volume and intermolecular forces.