GenChem4th_Part II

Which of the following statement is NOT true?

• Spontaneous process is reversible reaction.

• Heat flows from hotter objects to a colder one is a spontaneous process.

• For a chemical reaction to be spontaneous, it should proceed without an input of energy.

• If heat flows into the surroundings, the random motion of the molecules in the surroundings increases.

Applying the general rules, predict the entropy change of the system of the chemical reaction: 2H₂(g) + O₂(g) → 2H₂O(l)?

• Positive. Increase in number of gas molecules.      

• Negative. Decrease in number of gas particles.

• Positive. Gas molecules are converted liquid products

• Negative. Net decrease in number of molecules and gases are converted to liquids.

In predicting entropy change of the system, which of the following is NOT true?

• A.  If the total number of gas molecules diminishes, ΔS⁰ is negative.

•   If liquid molecules are converted to solid molecules, ΔS⁰ is positive.

• If the reaction produces more gas molecules than it consumes, ΔS⁰ is positive.

• If there is no net change in the total number of gas molecules, ΔS⁰ may be positive or negative, but will be relatively small numerically.

Methane is one of the components of LPG. So every time you cook your food in your gas stoves, you are burning methane. The Δ𝐺 for the following reaction at 25⁰C is −803.8𝑘𝐽. What is the direction of the spontaneity of the reaction?

• Forward direction  

• Backward Direction                 

• Reverse Direction           

• Stable Condition

On the basis of Δ𝐺⁰ for each of the following reactions, what is the spontaneity of the reaction?

NH₄Cl(s) → NH₃(g) + HCl(g)                 Δ𝐺⁰ =92 𝑘𝐽

• The reaction is spontaneous in the forward direction

• The reaction is spontaneous in the opposite direction.

• The reaction is non-spontaneous. It is spontaneous in the opposite direction.

• A. The reaction is non-spontaneous. It is spontaneous in the opposite direction.

During a hot summer day when you buy some solidified water (ice) then you put it in a glass jar. After some time, the ice will turn to liquid because of the very hot temperature. The vaporization of water in a closed container at a given temperature is an example. What reversible reaction is illustrated?  

• Chemical Reaction   

• Physical Equilibrium

• Chemical Equilibrium      

• Equilibrium Constant

How will you write the equilibrium constant, K_c for the reversible reactions at equilibrium:  

HF (aq) + H₂O (l) ⇌H₃O+ (aq) + F- (aq)?

• K_𝑐=[𝐻₃𝑂⁺] [𝐹−]/ [𝐻𝐹]          

• K_𝑐=[ 𝐹−] / [𝐻₃𝑂⁺][𝐻𝐹]           

• K_𝑐= [𝐹−][𝐻𝐹] / [𝐻₃𝑂⁺]         

• K_𝑐= [𝐻𝐹] / [𝐻₃𝑂⁺] [𝐹−]

Carbonyl chloride (phosgene) was used in WWI as a poisonous gas. At 74⁰C, [CO] = 1.2 X 10^-2 M, [Cl²] = 0.054 M, and [COCl²] = 0. 14 M. the computed K_c is 2165.49. How will you write your conclusion?

• The equilibrium will be stable.

• The equilibrium will lie to the right and it favours the reactant.

• The equilibrium will lie to the right and it favours the product.

• The equilibrium will lie to the right and it favours the reactant and the product.

Conjugate acid-base pair is defined as an acid and its conjugate base or abase and its conjugate acid. Conjugate Acid - an species that forms after a base accepts the Hydrogen ion (H+). In the chemical equation: HPO₄^2-(aq) + H₂O(l) ⇌ H₂PO₄^-(aq) + OH- , which is the conjugate acid?  

• HPO₄^2-(aq)      

• H₂O(l)         

• H₂PO₄^-

• D. OH^-

Solid potassium hydroxide dissociates in water to yield potassium ions and hydroxide ions. What type of solution is being illustrated?

• Acidic Solution              

• Basic Solution

• Neutral Solution

• Neutral Solution