Chemistry Equilibrium Constant and Reaction Quotient

Equilibrium Constant (K)

• The equilibrium constant (K) is a unitless value used to calculate the extent of a reaction's conversion from reactants to products at equilibrium.

• Kp and Kc are equilibrium constants for partial pressures and molar concentrations, respectively.

• If np > nr, then Δn is positive, and Kp > Kc.

• For example, the reaction PCl5(g) ⇌ PCl3(g) + Cl2(g)

  • Δn = 2 - 1 = 1
  • Kp > Kc

• A larger K value indicates a greater extent to which reactants are converted into products.

  • If K is small, the equilibrium favors the reactants.
  • If K is large, the products dominate.

Reaction Quotient (Q)

• Q is calculated using the same expression as the equilibrium constant but can be calculated at any point during the reaction.
  • If Q > K, the net reaction proceeds in the backward direction toward the reactants.
  • If Q < K, the net reaction proceeds in the forward direction toward the products.
  • If Q = K, the reaction is at equilibrium.

Relationships Between Equilibrium Constants

• K'c = 1/Kc
• K'c = (Kc)n
• K'c = √(Kc)
• K = K1 x K2

Le Chatelier's Principle

• Le Chatelier's principle states that a system at equilibrium will shift to counteract any changes in conditions.
  • These changes can include changes in concentration, pressure, or temperature.

e-TECHNO

• In a perfectly elastic collision, the total kinetic energy is conserved before and after the collision.
• The coefficient of restitution (e) measures the elasticity of a collision.
  • e = (v2 - v1) / (u1 - u2)
  • where v1 and v2 are the final velocities and u1 and u2 are the initial velocities of the colliding bodies.
  • The value of e ranges from 0 to 1.

Trigonometric Ratios and Quadrants

• Sine, cosine, tangent, cotangent, secant, and cosecant are the trigonometric ratios used in trigonometry.
• The sign of trigonometric ratios changes depending on the quadrant (1 to 4) of the unit circle.
• The line of sight is the line drawn from the observer's eye to a point on an object.
• The angle of elevation is the angle between the horizontal and the line of sight when the object is above the horizontal level.
• The angle of depression is the angle between the horizontal and the line of sight when the object is below the horizontal level.