Acertain reaction has an equilibrium constant of 3.5 × 108 at 25°c and 6.0 × 10–2 at 500°c. is the reaction exothermic or endothermic?

The reaction is exothermic.

Explanation:

When the temperature changes in a balanced system, it ceases to be in equilibrium because the value of the equilibrium constant is modified. Thus, at a temperature T1 the constant is K1, and at a temperature T2, the constant is K2. The relationship between these magnitudes is given in the so-called Van't Hoff equation.

The Wan't Hoff equation is:

Where:

ΔH: standard enthalpy of the reaction

R: constant of ideal gases

K1: equilibrium constant at temperature T1

K2: equilibrium constant at temperature T2

The Van't Hoff equation allows us to study how the chemical equilibrium shifts with temperature depending on whether we have an endothermic or exothermic reaction. So if the reaction is exothermic, ΔH <0, increasing the temperature decreases the equilibrium constant and the reaction moves to the left, while if the temperature decreases, the equilibrium constant increases and the equilibrium moves to the right.

Therefore, given the values of the equilibrium constant at different temperatures and observing that it decreases when the temperature rises, the reaction is exothermic.

what are the óptions. pléase list them

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.