Chapter 5: Properties of Gases, Kinetic Molecular Theory, and Real Gases

Vocabulary flashcards covering the properties of gases, barometric pressure, gas stoichiometry over water, Kinetic Molecular Theory, and real gas deviations using the van der Waals equation.

States of Matter (Particle Arrangement)

The classification of matter into solid (particles packed tightly in an orderly arrangement with minimal motion), liquid (particles in close contact with irregular arrangement and ability to slide past each other), and gas (particles separated by large distances moving freely in random directions).

Mercury Barometer

A device designed to measure atmospheric pressure, in which the external air pressure pushing down on an open dish of mercury counterbalances the weight of a column of mercury inside an inverted closed tube with a vacuum at the top.

Standard Atmosphere (in mm Hg)

The standard reference value for atmospheric pressure that supports a column of mercury of height $h = 760\text{ mm Hg}$ in a barometer.

Gas Mixture Bulb Apparatus

A laboratory apparatus consisting of two bulbs separated by a central stopcock (such as a left bulb containing $2.00\text{ atm}$ in $9.00\text{ L}$ and a right bulb containing $3.00\text{ atm}$ in $3.00\text{ L}$), used to measure final equilibrium pressures or gaseous reactions upon opening the valve.

Gas Collection Over Water

A laboratory technique where an insoluble or sparingly soluble gas produced by a chemical reaction is bubbled through a water bath and collected by displacing water in an inverted vessel, producing a gas mixture saturated with water vapor.

Thermal Decomposition of Potassium Chlorate

The chemical decomposition of solid potassium chlorate in the presence of a manganese dioxide ($MnO_2$) catalyst upon heating: $2KClO_3(s) \rightarrow 2KCl(s) + 3O_2(g)$.

Vapor Pressure of Water ($P_{H_2O}$)

The partial pressure exerted by water vapor in equilibrium with liquid water at a given temperature (such as $21\text{ torr}$ at $22\,^\circ\text{C}$), which must be subtracted from the total barometric pressure to obtain the partial pressure of a dry gas collected over water.

Kinetic Molecular Theory (KMT)

A model that explains the physical behavior of ideal gases based on the motion, collisions, and kinetic energy of microscopic gas particles.

Maxwell-Boltzmann Velocity Distribution

A distribution curve showing the fraction of gas molecules at each root-mean-square (rms) velocity; as temperature increases from $100\text{ K}$ to $1000\text{ K}$, the curve broadens and its peak shifts to higher velocities.

Compressibility Factor Deviation with Temperature

The deviation of $\frac{PV}{nRT}$ from ideal gas behavior ($\frac{PV}{nRT} = 1.0$) as a function of temperature; at lower temperatures like $203\text{ K}$, intermolecular attractions cause $\frac{PV}{nRT}$ to dip significantly below $1.0$ at moderate pressures, whereas at high temperatures like $673\text{ K}$, it remains near or above $1.0$.

Compressibility Factor Deviation Across Real Gases

The varying non-ideal behavior observed when plotting $\frac{PV}{nRT}$ against pressure for different gases ($N_2$, $CH_4$, $H_2$, $CO_2$) at $200\text{ K}$, displaying significant dips due to attractive forces followed by steep rises due to molecular volume at high pressures.

Van der Waals Equation

An equation of state for real gases that incorporates empirical constants to correct for intermolecular attraction and finite particle volume: $\left[P_{\text{obs}} + a\left(\frac{n}{V}\right)^2\right](V - nb) = nRT$.

Van der Waals Constant $a$

A parameter in the van der Waals equation expressed in units of $\frac{\text{atm}\cdot\text{L}^2}{\text{mol}^2}$ that accounts for the attractive forces between gas molecules.

Van der Waals Constant $b$

A parameter in the van der Waals equation expressed in units of $\frac{\text{L}}{\text{mol}}$ that accounts for the finite volume occupied by one mole of gas particles.