Regents Chemistry Exam August 2025 Question 21 21 Which expression represents the heat of reaction for a chemical change? (potential energy of the products) - (potential energy of the reactants) (potential energy of the products) + (potential energy of the reactants) (kinetic energy of the products) - (kinetic energy of the reactants) (kinetic energy of the products) + (kinetic energy of the reactants) Solution: Heat of reactions is equal to the potential energy of the produc

Regents Chemistry Exam August 2025 Question 20 20 When a system is at equilibrium, the concentrations of the reactants and the products must be (1) equal (3) decreasing (2) constant (4) increasing Solution: There are two things we have to know about systems at equilibrium. First, the rate of forward reaction has to be equal to the rate of reverse reaction. Second, the concentrations of reactants and products have to stay constant. Choice 2 is the correct answer. LINKS: Regent