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Q1.) Consider this reaction between solid sulfur and oxygen gas. H = 791.4 kJ/mo

ID: 534571 • Letter: Q

Question

Q1.) Consider this reaction between solid sulfur and oxygen gas.

H = 791.4 kJ/mol

When chemical systems are subjected to stresses, the equilibrium position may shift toward the reactants or products, or it may be unaffected. How would each of the following changes affect this equilibrium?

(a) increasing the temperature

shifts the reaction toward the reactants

shifts the reaction toward the products   

does not affect equilibrium


(b) increasing [O2]

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(c) increasing the volume of the container

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(d) adding S

shifts the reaction toward the reactants

shifts the reaction toward the products   

does not affect equilibrium


(e) adding an inert gas to increase the pressure

shifts the reaction toward the reactants

shifts the reaction toward the products   

does not affect equilibrium

Q2.) Consider this reaction between solid carbon and carbon dioxide gas.

H = +172.5 kJ/mol

When chemical systems are subjected to stresses, the equilibrium position may shift toward the reactants or products, or it may be unaffected. How would each of the following changes affect this equilibrium?

(a) decreasing the temperature

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(b) increasing [CO]

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(c) increasing the volume of the container

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(d) adding C

shifts the reaction toward the reactants

shifts the reaction toward the products

does not affect equilibrium


(e) adding a catalyst

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium

Q3.) Consider this reaction between solid iron and water vapor.

H = 151.2 kJ/mol

When chemical systems are subjected to stresses, the equilibrium position may shift toward the reactants or products, or it may be unaffected. How would each of the following changes affect this equilibrium? (There is only ONE submission for each part.)

(a) increasing the temperature

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(b) adding Fe

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(c) increasing the volume of the container

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(d) increasing [H2O]

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium


(e) increasing the pressure (and decreasing the volume) on the system

shifts the reaction toward the reactants

shifts the reaction toward the products    

does not affect equilibrium

Explanation / Answer

Q1.)

(a) increasing the temperature shifts the reaction toward the reactants

Negative value of enthalpy change for the reaction indicates exothermic nature of the reaction. Heat will appear on the products side of the reaction.
Reactant = Product + Heat
With increase in the temperature, heat is provided. To nullify the effect of added heat, the equilibrium will shift to left.

(b) increasing [O2] shifts the reaction toward the products
Oxygen is one of the reactants. When the reactant concentration increases, the equilibrium will shift to right. More and more reactants will be converted into products. This will decrease the reactant concentration and will nullify the effect of increase in [O2].

(c) increasing the volume of the container shifts the reaction toward the reactants.

With increase in the volume, the pressure decreases. The equilibrium will shift to the side containing more number of moles of gasesous species. Reactants contains 3 moles and products contain 2 moles of gaseous species.

(d) adding S does not affect equilibrium
S is a solid and its concetration remains unchanged during course of the reaction.

(e) adding an inert gas to increase the pressure shifts the reaction toward the reactants.
Total pressure will increase on addition of inert gas. The reaction will shift towards the side containing fewer number of moles of gaseous species.