Gas Laws: Boyle's, Charles' and Gay Lussac's Laws

Gas Laws

• Standard temperature is measured in Kelvin (K) and standard pressure is 1 atm, 760 mmHg or torr, 76 cmHg, 1.01325 x 10^6 dynes/cm^2, 1.01325 x 10^5 Pa or N/m^2, or 1.01325 bar.
• Boyle's Law states that at constant temperature, an increase in pressure results in a decrease in volume, and they are inversely related (P1V1 = P2V2).
• Charles' Law states that at constant pressure, an increase in temperature results in an increase in volume, and they are directly related (T1/V1 = T2/V2).

Avogadro's Law and the Combined Gas Law

• Avogadro's Law states that equal volumes of gases at the same temperature and pressure contain an equal number of molecules (V1/n1 = V2/n2).
• The Combined Gas Law is derived from Boyle's Law, Charles' Law, and Avogadro's Law (P1V1/T1 = P2V2/T2).
• The Ideal Gas Law is PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the universal gas constant, and T is temperature in Kelvin.

Dalton's Law of Partial Pressure

• Dalton's Law of Partial Pressure states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas (Ptotal = P1 + P2 + P3 + ...).
• The partial pressure of a gas is equal to the mole fraction of the gas multiplied by the total pressure (PA = XA * Ptotal).

Clausius Clapeyron Equation

• The Clausius Clapeyron Equation is used to calculate the vapor pressure of a substance at a given temperature, and is given by log(P2/P1) = ΔHv / (2.303RT1T2).

Intermolecular Forces

• Van der Waals forces include dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole forces.
• Ion-induced dipole forces occur between ions and non-polar molecules.
• Hydrogen bonding occurs between hydrogen atoms and electronegative atoms such as N, O, and F.

Kinetic Molecular Theory

• The Kinetic Molecular Theory states that gases are composed of small particles called atoms, which exhibit continuous random motion and do not attract or repel each other.
• The theory also states that the total volume of the particles is negligible compared to the space they occupy, and that gases exhibit perfect elasticity.

Rheology

• Rheology is the study of the flow and deformation of materials.
• Absolute viscosity (η) is a measure of a fluid's resistance to flow, and is measured in poise (ρ) or dynes-s/cm^2.
• Kinematic viscosity is the ratio of absolute viscosity to density, and is measured in stokes.
• Relative viscosity is the ratio of the absolute viscosity of a fluid to the absolute viscosity of a reference fluid.

Factors Affecting Viscosity

• The viscosity of a gas increases with temperature, while the viscosity of a liquid decreases with temperature.
• The viscosity of a liquid decreases with molecular weight, and increases with the addition of electrolytes or organic substances.

Newton's Law of Flow

• Newton's Law of Flow states that the shear stress required to produce a certain rate of shear is proportional to the viscosity of the fluid (F = η * G).

Types of Flow

• Pseudoplastic flow is characterized by shear thinning behavior, and is exhibited by polymers in solution.
• Dilatant flow is characterized by shear thickening behavior, and is associated with particles that do not tend to aggregate or stick together.