Alberta Free Tutoring And Homework Help For Chemistry 30

  0

0 Tutors Online Right Now

THE FOLLOWING SYSTEM WAS HEATED 

H2(g) + I2(g) + 53kJ ---> 2HI(g) 

identify the effect of the temperature increase on the concentation of HI and on Kc of this system. 

choose either it decreases or increases for both 

Concentation of HI= 

Kc= 

question 2 

consider the following equalibrium 

BaS(s)--> Ba2+(aq) + S2-(aq)

when Ba(NO3)2(aq) is added to this solution the equalibirum shifts to the ________ and the concentration of the sulfide ions___________ 

choose either right or left for the shift 

and choose decrease or increase for the concentration of ions

P.S THE ARROWS ARE SUPPOSED TO BE MEANT AS REVERSE AND FORWARD 

6 years ago

Answered By Leonardo F

This question involves the concept of chemical equilibrium shift. In question 1, since the 53 kJ is on the left side of the equation, we know that this reaction is endothermic, because it must absorb 53 kJ of energy for the reaction to occur. Hence, we know that the direct reaction (production of HI) is endothermic, while the reverse reaction (production of H2 and I2) is exothermic. Since an increase in temperature shifts the equilibrium to the endothermic side, an increase of temperature will increase the concentration of HI. Since the equilibrium constant is the concentration of the products divided by the reactants, and the concentration of the product is increasing, Kc will definitely increase with an increase of temperature. Hence:

Concentration of HI: increases

KC: increases

Question 2) Since Ba2+ is a common ion to the solution, when we add Ba(NO3)2 to the solution, we will increase the concentration of Ba2+ ions. This causes the equilibrium to shift to the opposite side. So, the equilibrium shifts to the left. The concentration of the sulfide ions will decrease in consequence, because S2- is on the right side and the equilibrium is shifted to the left.