THERMODYNAMICS Quiz-10

CHEMISTRY THERMODYNAMICS QUIZ-10

Dear Readers,

IIT JEE exam which consists of JEE Main and JEE Advanced is one of the most important entrance exams for engineering aspirants. The exam is held for candidates who are aspiring to pursue a career in the field of engineering and technical studies.
Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..

Q1.In which reaction(s), ∆S is negative?:

•  H₂O(l) → >H₂O(s)
•  3O₂(g) → 2O₃(g)
•  H₂O(l) → >H₂O(g)
•   N₂(g) + 3H₂(g) → 2NH₃(g)

Solution
(a,b,d)
In all these conversion, the degree of randomness decreases

Q2.For the adiabatic expansion of an ideal gas

•  PV^γ = constant
•  TV^γ-1 = constant
•  TP^1-γ = constant
•  None of the above

Solution
(a,b,c)
Mathematical relation

Q3.For which process does ∆U = 0 holds true?

•  Cyclic process
•  Isothermal expansion
•  Isochoric process
•  Adiabatic process

Solution
(a,b)
∆U = 0 for cyclic and isothermal process

Q4.Which of the following statements is/are correct?

•  The evaporation of water is an endothermic change
•  The conversion of white phosphorus to red phosphorus to red phosphorus is an exothermic reaction
•  The heat of neutralization of a strong acid with a strong base is always the same
•  ∆H is negative for endothermic reactions

Solution
(a,b,c)

Q5.For which of the following substances is the heat of formation in the standard state zero?

•  Sugar
•  C_diamond
•  Zinc
•  C_graphite

Solution
 (c,d)

Q6.The standard heat of formation of a compound is the:

•  Change in enthalpy for the production of 1 mole of the compound at STP
•  Change in enthalpy for the formation of 1 mole of the compound form its elements
• Change in enthalpy for the formation of 1 mole of the compound form its elements at 298 K and 1 atmospheric pressure
•  Change in enthalpy for the formation of 1 mole of the compound form its elements at 25°C and a pressure of 760 mm of Hg.

Solution
(c,d)

Q7.In which of the following cases, do you consider the increase in entropy take(s) place?

•  Pure liquid or liquid solutions are formed from solids
•  Gases are formed, either from solids or liquids
•  The number of molecules of gases increase in the course of a chemical reaction
•  The temperature of a substance is increased

Solution
(a,b,c,d)

Q8.Which of the following statements is/are correct?

•  The heat of neutralization of a strong acid with a strong base is always the same
•  The enthalpy of combustion is always negative
•  A spontaneous change involves a lowering of free energy
•  The enthalpy of an element in the standard state assumed to be unity at 298 K.

Solution
(a,b,c)

Q9.In which of the following cases is the reaction spontaneous at all temperatures?

•  ∆H > 0 , ∆S > 0
•  ∆H < 0 , ∆S > 0
•  ∆H < 0 , ∆S < 0
•  ∆H < 0 , ∆S = 0

Solution
∆H < 0 , ∆S > 0

Q10. The internal energy (U) of an ideal gas decreases by the same amount as the work done by the system:

•  The process must be adiabatic
•  The process must be isothermal
•  The process must be isobaric
•  The temperature must decrease

Solution
(a,d)