1) If more reactant is added to a gaseous reaction at equilibrium, what will happen to the value of the equilibrium constant?
a. it will increase
b. it will decrease
c. it will remain the same
d. it can either increase or decrease
2) Which of the following describes a property at the microscopic level?
a. the brown colour of nitrogen dioxide gas
b. the odour of ammonia gas
c. a temperature increase
d. a collision between NO2 molecules
3) For any reversible reaction at equilibrium
a. the concentrations of the products and reactants must be equal
b. the rates of forward and reverse reactions are equal
c. both a and b are true
d. neither a nor b is true
4) If the temperature of a reaction increases, what will happen to the value of the equilibrium constant?
a. it will increase
b. it will decrease
c. it will remain the same
d. it can either increase or decrease
Help. Please. This is due in a few minutes.
1) To determine what will happen to the value of the equilibrium constant when more reactant is added to a gaseous reaction at equilibrium, we need to understand Le Chatelier's principle. According to this principle, a system at equilibrium will shift in a way that counteracts the imposed change.
In this case, adding more reactant would disturb the equilibrium by increasing the concentration of the reactant. To counteract this increase, the system will shift in the direction that consumes some of the reactant. This means the forward reaction will be favored, leading to an increase in the concentration of the products.
Since the equilibrium constant (K) is a ratio of the concentrations of products to reactants at equilibrium, an increase in the concentration of the products will result in an increase in the value of the equilibrium constant.
Therefore, the answer is: a) It will increase.
2) Among the given options, the property that describes a microscopic level phenomenon is d) a collision between NO2 molecules. This is because a collision between molecules is a characteristic of the behavior of individual particles at a microscopic level.
The brown color of nitrogen dioxide gas (a) and the odor of ammonia gas (b) are both macroscopic properties that can be observed without considering the individual particles. A temperature increase (c) is a change in the overall energy of the system and can be considered at a macroscopic level.
3) For any reversible reaction at equilibrium, both the concentrations of the products and reactants are not necessarily equal. This eliminates option a) as the correct answer.
However, according to the principle of microscopic reversibility, the rates of the forward and reverse reactions at equilibrium are equal. This means that the system has reached a dynamic state in which the forward and reverse reactions occur at the same rate. Therefore, the answer is: b) The rates of forward and reverse reactions are equal.
4) When the temperature of a reaction increases, the value of the equilibrium constant can either increase or decrease depending on whether the reaction is exothermic or endothermic.
For an exothermic reaction (releases heat), increasing the temperature will shift the equilibrium in the backward direction to consume excess heat. This will result in a decrease in the concentration of the products and an increase in the concentration of the reactants. As a consequence, the equilibrium constant will decrease.
Conversely, for an endothermic reaction (absorbs heat), increasing the temperature will shift the equilibrium in the forward direction to absorb more heat. This will result in an increase in the concentration of the products and a decrease in the concentration of the reactants. As a consequence, the equilibrium constant will increase.
Therefore, the answer is: d) It can either increase or decrease.