Regents Chemistry June 2026 18 LeChatelier’s principle can be used to predict the (1) reactivity of a metal (2) volume of a gas at STP (3) concentration of an aqueous solution (4) effect of a stress on a system at equilibrium Solution: Le Chatelier's principle states that if there is a stress on a system that takes it away from the equibrium position, the system will react in such as way as to reestablish the equilibrium. Choice 4 is the correct answer. LINKS: Regents Chemist

Regents Chemistry June 2026 17 Based on Table I, which compound is formed from its elements at 101.3 kPa and 298 K by an endothermic reaction? (1) CO2 (2) NO2 (3) C2H6 (4) NH3 Solution: Table I lists chemical reactions and the values of ΔH associated with these reactions. If ΔH is positive, this means the reaction is endothermic (heat is absorbed) and if it is negative, this means the reaction is exothermic (heat is being released). We need to find the reaction for creation o