What is true about the equilibrium state?

Both forward and reverse reactions continue at the same rate.

Both forward and reverse reactions stops.

Total mass of reactants and products

Chemistry Quiz: Chemical Equilibrium

2.

When a mixture of H2 and I2 is sealed in a flask and temperature is kept at 25o C?
Which substance or substances will be present in the equilibrium mixture? - ProProfs

When a mixture of H₂and I₂is sealed in a flask and temperature is kept at 25^oC? Which substance or substances will be present in the equilibrium mixture?

H2 and I2
H2 only
H2 only
H2, I2 and HI

Correct Answer

A. H2, I2 and HI

Explanation

At a temperature of 25°C, the mixture of H2 and I2 will reach equilibrium. This means that both H2 and I2 will be present in the equilibrium mixture. Additionally, the presence of HI in the equilibrium mixture suggests that a reaction has occurred between H2 and I2 to form HI. Therefore, the correct answer is H2, I2, and HI.

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3.

What are the units for?

Mol.dm^-3
Mol².dm⁶
Dm3.mol^-1
No units

Correct Answer

A. No units

Explanation

The answer "No units" is correct because the given options are all unit expressions, except for the last one. The first three options have units of concentration, with the first option representing moles per cubic decimeter (mol.dm-3), the second option representing moles squared per cubic decimeter to the power of 6 (mol2.dm6), and the third option representing cubic decimeters per mole (dm3.mol-1). However, the last option, "No units," indicates that there are no units associated with it, suggesting that it is not a valid unit expression.

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4.

Which of the following reactions will not have any units for Kc?

Option 1
Option 2
Option 3
All of these

Correct Answer

A. All of these

Explanation

All of the reactions mentioned in the options will not have any units for Kc. This is because the units of Kc depend on the stoichiometric coefficients of the balanced chemical equation. If all the stoichiometric coefficients are dimensionless, then the units of Kc will also be dimensionless. In other words, if the reaction does not involve any substances with units (such as molarity or concentration), then the Kc value will not have any units. Therefore, all of the given reactions will not have any units for Kc.

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5.

Concentrations of reactants and products at equilibrium remain unchanged if ?

Concentration of any reactant or product is not changed
Temperature of reaction is not changed
Pressure or volume of the system is not changed
All of the above are observed

Correct Answer

A. All of the above are observed

Explanation

At equilibrium, the concentrations of reactants and products remain unchanged because the forward and backward reactions are occurring at the same rate. This means that the rate of formation of products is equal to the rate of formation of reactants. If the concentration of any reactant or product is changed, the equilibrium will shift to restore the balance and maintain the concentrations. Similarly, if the temperature, pressure, or volume of the system is changed, the equilibrium will also shift to maintain the concentrations. Therefore, all of the above observations are true for concentrations of reactants and products to remain unchanged at equilibrium.

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6.

Which of the following does not happen, when system is at equilibrium?

Forward and reverse reaction stop.
Forward and reverse reaction become equal.
Concentration of reactant and product stop changing.
Reaction continues to occur in both directions

Correct Answer

A. Forward and reverse reaction stop.

Explanation

When a system is at equilibrium, the forward and reverse reactions are still occurring, but at the same rate. This means that the concentrations of reactants and products are no longer changing, as the rates of the forward and reverse reactions are equal. Therefore, the statement "Forward and reverse reaction stop" is incorrect because the reactions are still happening, just at equal rates.

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7.

For which reaction, Kc has units of mol.dm^-3?

Option 1
Option 2
Option 3
Option 4

Correct Answer

A. Option 3

Explanation

The question is asking for the reaction in which the equilibrium constant, Kc, has units of mol.dm-3. This indicates that the equilibrium constant is expressed in terms of concentrations of the reactants and products. Option 3 is the correct answer because it is the only option that represents a reaction where the equilibrium constant is defined in terms of concentrations.

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8.

In irreversible reaction, equilibrium is?

Established quickly
Established slowly
Never established
Established when reaction stops.

Correct Answer

A. Never established

Explanation

In an irreversible reaction, equilibrium is never established because the reaction proceeds in one direction only and does not have the ability to reach a state of balance between the reactants and products. Unlike reversible reactions, where equilibrium can be achieved when the forward and backward reactions occur at equal rates, irreversible reactions continue until one or more of the reactants are completely consumed. Therefore, equilibrium is not possible in irreversible reactions.

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9.

Active mass means?

Total mass of reactants
Total mass of products
Total mass of reactants and products
Mass of substance in mole per dm^-3 in a dilute solution

Correct Answer

A. Mass of substance in mole per dm^-3 in a dilute solution

Explanation

Active mass refers to the concentration of a substance in a solution, specifically the mass of the substance per unit volume of the solution. It is commonly expressed in moles per cubic decimeter (dm-3) in a dilute solution. This term is used to describe the amount of a substance that is available for a chemical reaction to occur. The active mass is important in determining the rate of reaction and the equilibrium constant of a chemical reaction.

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10.

For a reversible reaction, Which substance is product of the reaction?

A
B
Both A and B
C

Correct Answer

A. A

Explanation

In a reversible reaction, both reactants can convert into products and vice versa. However, the question specifically asks for the substance that is a product of the reaction. Therefore, the correct answer is A, indicating that substance A is the product of the reversible reaction.

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Chemistry Quiz: Chemical Equilibrium

What is true about the equilibrium state?

Quiz Preview

When a mixture of H2 and I2 is sealed in a flask and temperature is kept at 25o C? Which substance or substances will be present in the equilibrium mixture?

What are the units for?

Which of the following reactions will not have any units for Kc?

Concentrations of reactants and products at equilibrium remain unchanged if ?

Which of the following does not happen, when system is at equilibrium?

For which reaction, Kc has units of mol.dm-3?

In irreversible reaction, equilibrium is?

Active mass means?

For a reversible reaction, Which substance is product of the reaction?

When a mixture of H₂and I₂is sealed in a flask and temperature is kept at 25^oC? Which substance or substances will be present in the equilibrium mixture?

For which reaction, Kc has units of mol.dm^-3?