FULL SOLUTIONS AND CORRECT ANSWERS
GRADED A+
⩥ What is the standard state for elements? Answer: 25°C and 1 atm (or
100 kPa).
⩥ What is the ΔH°f for elements in their standard state? Answer: 0
kJ/mol.
⩥ How do you calculate ΔH°rxn from ΔH°f? Answer: ΔH°rxn = Σ(n ×
ΔH°f products) - Σ(n × ΔH°f reactants).
⩥ What is dynamic equilibrium? Answer: A state where forward and
reverse reactions occur at the same rate, with constant concentrations.
⩥ What happens to the equilibrium when stress is applied according to
Le Chatelier's Principle? Answer: The system shifts to reduce the stress.
⩥ What is the effect of increasing temperature on an endothermic
reaction? Answer: The equilibrium constant (K) increases, shifting the
reaction to the right.
, ⩥ What is the effect of increasing pressure on a gas equilibrium?
Answer: The equilibrium shifts to the side with fewer moles of gas.
⩥ What does the equilibrium constant (K) represent? Answer: The ratio
of the concentrations of products to reactants at equilibrium.
⩥ What is the reaction quotient (Q)? Answer: It is the same expression
as K but uses non-equilibrium concentrations.
⩥ How does a catalyst affect equilibrium? Answer: It does not change
the position of equilibrium but allows it to be reached faster.
⩥ What is an ICE table used for? Answer: To find equilibrium
concentrations by organizing initial concentrations, changes, and
equilibrium values.
⩥ What is the solubility product (Ksp)? Answer: The equilibrium
constant for a slightly soluble ionic compound.
⩥ What does it mean if Qsp < Ksp? Answer: The solution is unsaturated,
and no precipitate will form.
⩥ What is the Haber process used for? Answer: To synthesize ammonia
(NH₃) from nitrogen (N₂) and hydrogen (H₂).