Correctly To Score A+ 2025
Dynamic Equilibrium CORRECT ANSWERS For a chemical reaction, the condition in
which the rate of the forward reaction equals the rate of the reverse reaction.
Equilibrium Constant (K) CORRECT ANSWERS The ratio (at equilibrium) of the
concentrations of the products raised to their stoichiometric coefficients divided by the
concentrations of the reactants raised to their stoichiometric coefficients.
aA+bB↔cC+dD
K=([C]^c[D]^d)/([A]^a[B]^b)=[products]/[reactants]
Relative Size of Keq CORRECT ANSWERS If K>>1, reaction proceeds forward; favors
products
If K<<1, reaction proceeds a little; favors reactants
If K≈1, reaction proceeds about half way
Relationships Between Keq and the Chemical Equation CORRECT ANSWERS If the
reaction is reversed: Kreverse = 1/Kforward
If the coefficients in the equation are multiplied by a factor: raise the equilibrium
constant to the same factor
If two or more individual chemical equations are added: multiply the corresponding
equilibrium constants by each other to obtain the overall Keq
Heterogeneous Equilibria Involving Solids and Liquids CORRECT ANSWERS The
concentrations of pure liquids and solids remain constant and are therefore excluded
from the equilibrium expression.
Expressing Keq in Terms of Pressure CORRECT ANSWERS Kp=Kc(RT)^(∆n)
where Kp is the equilibrium constant with respect to partial pressures in atm, Kc is the
equilibrium constant with respect to concentration, R=0.08206 L·atm/mol·K, T is
temperature in K, and ∆n is the change in number of moles of gas
Reaction Quotient (Qc) CORRECT ANSWERS the ratio (at any point in the reaction) of
the concentrations of the products raised to their stoichiometric coefficients divided by
the concentrations of the reactants raised to their stoichiometric coefficients.
Q, K, and the Direction of a Reaction CORRECT ANSWERS If Q<K, reaction goes
forward (toward products)
If Q=K, reaction is at equilibrium
If Q>K, reaction goes backwards (toward reactants)
, Le Châtelier's Principle CORRECT ANSWERS When a chemical system at equilibrium
is disturbed, the system shifts in a direction that minimizes the disturbance.
Summary of Le Châtelier's Principle: Changes in Pressure CORRECT ANSWERS
Decreasing the volume causes the reaction to shift in the direction that has the fewer
moles of gas particles.
Increasing the volume cases the reaction to shift in the direction that has the greater
number of moles of gas particles.
If a reaction has an equal number of moles of both sides of the chemical equation, then
a change in volume produces no effect on the equilibrium.
Adding an inert gas to the mixture at a fixed volume has no effect on the equilibrium.
Summary of Le Châtelier's Principle: Changes in Concentration CORRECT ANSWERS
Increasing the concentration of one or more of the reactants (which makes Q<K) causes
the reaction to shift in the direction of the products.
Increasing the concentration of one or more of the products (which makes Q>K) causes
the reaction to shift in the direction of the reactants.
Decreasing the concentration of one or more of the reactants (which makes Q>K)
causes the reaction to shift in the direction of the reactants.
Decreasing the concentration of one or more of the products (which makes Q<K)
causes the reaction to shift in the direction of the products.
Summary of Le Châtelier's Principle: Changes in Temperature CORRECT ANSWERS
In an exothermic reaction:
Increasing the temperature causes an exothermic reaction to shift in the direction of the
reactants; the value of Keq decreases.
Decreasing the temperature causes an exothermic reaction to shift in the direction of
the products; the value of Keq increases.
In an endothermic reaction:
Increasing the temperature causes an endothermic reaction to shift in the direction of
the products; the value of Keq increases.
Decreasing the temperature causes an endothermic reaction to shift in the direction of
the reactants; the value of Keq decreases.
General Properties of Acids CORRECT ANSWERS sour taste, ability to dissolve many
metals, ability to turn blue litmus paper red, ability to neutralize bases
HCl CORRECT ANSWERS Hydrochloric Acid; a common acid
H₂SO₄ CORRECT ANSWERS Sulfuric Acid; a common acid (diprotic acid)
HNO₃ CORRECT ANSWERS Nitric Acid; a common acid
HC₂H₃O₂ CORRECT ANSWERS Acetic Acid; a common acid