Thermochemistry MCQs

Note: All MCQs related to Thermochemistry will be updated on this page.Answers to the MCQs are given in the comments section.

[page][item] 1-The process which once started will continue to happen without the intervention of outside sources is called
A Non-spontaneous process
B Continuous process
C Isobaric process
D Spontaneous process

2-Melting of ice at room temperature, rusting of iron and combustion of methane are
A Spontaneous and exothermic processes
B Spontaneous and endothermic processes
C Spontaneous and reversible processes
D Spontaneous processes

3-Ice can be melted at a room temperature below than 0C by applying pressure. The process is an example of a
A Physical change
B Non-spontaneous physical change
C Spontaneous physical change
D Non-spontaneous chemical change

4-If heat is supplied to the system and work is done on the system then first law of thermodynamics will take the form
A dE=q+w
B dE=q-w
C dE=-q+w
D dE=-q-w


5-Applying first law of thermodynamics to a gaseous system in which heat is released by the system and work is done on the system we get
A dE=q+w
B dE=q-w
C dE=-q+w
D dE=-q-w

6-Heat supplied to a system at constant pressure increases its
A Internal energy
B Volume
C Enthalpy
D Temperature

7-Applying first law of thermodynamics to a process in which volume of the gaseous system remains constant we get
A q=dE+w
B q=dE
C q =dH
D q=dE-w

8-Conditions under which standard enthalpy changes are measured are
A 273 K and 1 atm
B 0 C and 1 atm
C -273 C and 1 atm
D 25 C and 1 atm

9-The enthalpy change during the formation of one mole of a compound from its elements in their standard states is called
A Standard heat of reaction
B Standard heat of formation
C Standard heat of combustion
D Standard heat of neutralization


10-All of the following processes do not represent hydration except
A K+(g) + Cl-(g)------->KCl(s)
B Na+(g) +I-(g)--------->NaI(s)
C K+(g) + Br-(g)--------->KBr(aq)
D Na+(g) +Cl-(g)--------->NaCl(s)

[/item][item] 11-The enthalpy change during the dissolution of one mole of gaseous ions in water to produce infinitely dilute solution is known as
A Enthalpy change of solution
B Enthalpy change of hydration
C Enthalpy change of combustion
D Enthalpy change of neutralization

12-Heat of solution dH(sol) is related to lattice energy dH(L.E) and heat of hydration dH(h) by the equation
A dH(h) = dH(sol) - dH(L.E)
B dH(h) = dH(sol) + dH(L.E)
C dH(sol) = dH(h) + dH(L.E)
D dH(sol) = dH(L.E) - dH(h)

13-"The amount of heat evolved or absorbed in a chemical reaction is the same no matter the reaction takes place in one step or several steps" is statement of
A First law of thermodynamics
B Hess's law
C Law of mass action
D Raoult's law

14-All of the following processes do not represent ionization of sodium except
A Na(g)------->Na+(aq) +e
B Na(s)-------->Na+(g) +e
C Na(l)----->Na+(g)+e
D Na(g)-------->Na+(g) +e


15-Suppose you have a balloon of given volume V1, containing a gas at temperature T. When you place the balloon in a colder room at temperature T2, the balloon's temperature starts to drop. What are the signs of the system' q , w and dE for this process?
A +q, +w, +dE
B -q, -w, +dE
C +q, -w, -dE
D -q, +w, -dE

16-The melting of ice at room temperature is an endothermic process:
H2O(s)---->H2O(l)  dH=+6.0 kJ/mol.
Thus eating ice counteracts the exothermic processes of metabolizing food. How much ice (in grams) would you have to eat to counteract the energy gained by eating 28.3 g of peanuts (13 kJ/g)?
A 78 g
B 110 g
C 370 g
D 1100 g

17-In which of the following general chemical systems is work done on the surrounding and heat transferred from  the surroundings to the system?
A A(g) + B(g) ---------> AB(g)   q= -
B AB(g)------>A(g) + B(g)         q=+
C AB(g) + CD(g)--------> CB(g) + AD(g)    q=+
D A(g) +A(g)---------A2(g)        q=+

18-SO2(s)------->SO2(g) [32.3 kJ/mol]
SO2(l)------->SO2(g) [24.9 kJ/mol]
amount of energy for SO2(l)---->SO2(s) is
A 57.2 kJ/mol
B 7.4 kJ/mol
C -7.4 kJ/mol
D -57.2 kJ/mol

19-Which process is not endothermic?
A H2O(s)---->H2O(l)
B 2H2O(g)------>2H2(g) + O2(g)
C H2O(g)------->H2O(l)
D Al2O3(l) + 2Fe(l)-------> 2 Al(s) + Fe2O3(s)


20- 3/2O2(g) +2B(s)------>B2O3(s),  dH=-1264 kJ/mol;
O3(g) +2B(s)------->B2O(s),  dH=-1406 kJ/mol.
Calculate the enthalpy change for the reaction converting oxyden(O2(g)) to ozone O3(g) at 298 K and 1 atm.          
A -1264 kJ
B -2670 kJ
C -142 kJ
D +142 kJ

[/item][item] 21-Which of the following sequences of the dH associated with the phase changes of a particular substance is correct?
A dH(vaporization) < dH(sublimation) < dH(fusion) < dH(condensation)
B dH(fusion) < dH(condensation) < dH(sublimation) < dH(vaporization)
C dH(condensation) < dH(fusion) < dH(vaporization) < dH(sublimation)
D dH(condensation) < dH(sublimation) < dH(fusion) < dH(vaporization)

22-Which of the following is not a spontaneous process?
A Reaction of H2 with O2 to form H2O
B Combustion of natural gas
C Neutralization of HCl bu NaOH
D Synthesis of glucose by plants

23-Water can be produced in laboratory by the reaction  2H2 + O2---->2H2O. If H(f) is the heat of formation of H2O and H(r) is the heat of reaction then
A H(f)=H(r)
B H(f)=H(r)/2
C H(r)=H(f)/2
D H(f)=2H(r)

24-Sublimation, vaporization, melting and photosynthesis all are examples of
A Chemical processes
B Physical processes
C Biochemical processes
D Endothermic processes


25-X represent an unknown compound... X(s)---->X(g) [200 kJ/mol];
X(s)----->X(l) [8 kJ/mol]; X(l)------>X(g) [?}.
Calculate unknown enthalpy change.
A 192 kJ/mol
B 208 kJ/mol
C 16 kJ/mol
D 400 kJ/mol

26-A mixture of ice and water contains 60g of ice and 60g of water. If 60J of heat energy is removed from this mixture then
A Some of the water will vaporize
B Some of the ice will sublime
C Some of the ice will melt
D Some of the water will freeze

27-Zinc powder is sprinkled on aqueous solution of copper sulfate. Copper sulfate solution is decolorized. This is a
A Synthesis
B Decomposition
C Spontaneous process
D Non-spontaneous process

28-Dissolution of sodium chloride in water is a
A Non-spontaneous exothermic process
B Non-spontaneous endothermic process
C Spontaneous exothermic process
D Spontaneous endothermic process

29-Calorimeter is an apparatus used for the measurement of
A Mechanism of the reaction
B Order of the reaction
C Heat of the reaction
D Stoichiometry of the reaction


30-Born-Haber cycle is used for the measurement of
A Potantial energy
B Kinetic energy
C Chemical energy
D Lattice energy

[/item][item] 31-In the equation X=E+PV "X" represents
A Entropy of the system
B Enthalpy of the system
C Gas constant
D Heat lost by the system

32-Thermochemistry is the study of chemical reaction accompanying
A Heat change
B Rate change
C Mass change
D Volume change

33-When a bond breaks
A Heat is evolved
B Heat is absorbed
C No change in heat contents takes place
D Temperature increases

34-Which of the following is an endothermic reaction
A C(g) + O2(g)------>CO2(g)   dH= -3904 kJ/mol
B H2(g) +1/2O2 ------->H2O(g)   dH= -286 kJ/mol
C N2(g) + 3H2(g)-------->2NH3(g)  dH = -92 kJ/mol
D N2(g) + O2(g) ------------>2NO(g)  dH= +130 kJ/mol


35-Which one of the following is not a spontaneous reaction
A Flow of water from higher to lower level
B Neutralization of a strong acid with strong base
C When a piece of Zn is added to the blue copper sulfate solution the color disappears
D Formation of nitric oxide, NO, from N2 and H2 at room temperature

36-Which of the following is not a state function?
A Pressure
B Temperature
C Enthalpy
D Amount of substances

37-N2 and O2 are present in air but they do not react chemically at ordinary conditions of temperature and pressure because it is a
A Spontaneous reaction
B Reversible reaction
C Exothermic reaction
D Non-spontaneous reaction

38-Burning of coal in air is initiated by a spark and it is an example of a spontaneous reaction because
A Burning of coal in air releases large amount of energy
B Burning of coal is an endothermic process
C Coal and air react giving reversible reaction
D None of the above

39-A sample of matter under examination in laboratory of unit consideration in the classroom is called
A Sorrounding
B System
C Substance
D State function


40-A microscopic property of a system which describes the initial and final state of the system is called
A Physical property
B Chemical property
C Energy of system
D State function

Note: Mcqs related to Physical optics will be updated on this page.Answers to the mcqs will be given in the comments section.

[page][item] 1-One cannot see through fog because
A- Fog absorbs light
B- The refractive index of fog is infinity
C- Light suffers total reflection at the droplet of fog
D- Light is scattered by the droplets in fog

2-At sunrise or sunset, the sun looks reddish because
A The sun is coldest at these times
B Of the effects of reflection and refraction
C The sun is hottest at these times
D Of the scattering of light

3-A prism splits a beam of white light into its seven constituent colors. This is so because
A Phase of different colors is different
B Amplitude of different colors is different
C Energy of different colors is different
D Velocity of different colors is different

4-The twinkling of stars is due to
A The fact that stars do not emit light continuously
B The refractive index of the earth's atmosphere fluctuates
C Intermittent absorption of starlight by its own atmosphere
D None of these


5-Light appears to travel in straight lines since
A It is not absorbed by the atmosphere
B It is reflection by the atmosphere
C Its wavelength is very small
D Its velocity is very large

6-Which of the following phenomena is not explained by Huygen's construction of wavefront?
A Reflection
B Reflraction
C Diffraction
D Origin of spectra

7-If yellow light emitted by sodium lamp in Young's double slit experiment is replaced by monochromatic blue light of the same intensity
A Fringe width will decrease
B Fringe width will increase
C The fringe width will remain unchanged
D Fringes will become less intense

8-In Young's experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed one meter away. If it produces the dark fringe at a distance of 1 mm from the central fringe the wavelength of monochromatic light used would be
A 60 x 10^-4 cm
B 10 x10^-4 cm
C 10 x 10^-5 cm
D 6 x 0^-5 cm

9-The contrast in the fringes in any interference pattern depends on
A Fringe width
B Intensity ratio of sources
C Distance between slits
D Wavelengths


10-Huygen's wave theory of light cannot explain
A Diffraction
B Interference
C Polarization
D Photoelectric effect

[/item][item] 11-The sky appears blue because
A Red light is absorved
B Blue light is scattered the most
C Blue light is absorbed
D It is its natural color

12-Interference was observed in interference chamber when air was present, now the chamber is evacuated and if the same light is used, a careful observer will see
A No interference
B Interference with bright bands
C Interference with dark bands
D Interference in which breadth of the fringe will be slightly increase

13-Fraunhoffer spectrum is a
A Line absorption spectrum
B Band absorption spectrum
C Line emission spectrum
D Band emission spectrum

14-The speed of light in air is 3 x 10^8 m/s. What will be its speed in diamond whose refractive index is 2.4?
A 3 x 10^8 m/s
B 332 m/s
C 1.25 x 10^8 m/s
D 7.2 x 10^8 m/s


15-When light travels from one medium to another, which are separated by a sharp boundary, the characteristic which does not change is
A Velocity
B Wavelength
C Frequency
D Amplitude

16-Ray optics is valid when characteristic dimensions are
A Of the same order as the wavelength of light
B Much smaller than the wavelength of light
C Of the order of one millimeter
D Much larger than the wavelength of light

17-When seen in green light, the saffron and green portions of our National Flag will appear to be
A Black
B Black and green respectively
C Green
D Green and yellow respectively

18-If a source of light is moving away from stationary observer, then frequency of light wave appear to change because of
A Doppler's effect
B Interference
C Diffraction
D None f the above

19-For the sustained interference of light, the necessary condition os that the two sources should
A Have constant phase difference
B Be narrow
C Be close to each other
D Of same amplitude


20-A thin lens of focal length f has aperture d. It forms an image of intensity I. Inner part of the lens up to n diameter d/2 is painted black, the intensity of the image will be
A I/4
B I/2
C 3I/4

[/item][item] 21-In the Young's double slit experiment the separation between the slits is halved and the distance between slits and the screen is doubled. The fringe width is
A Halved
B Unchanged
C Doubled
D Quadrupled

22-When the light is incident on polarizing angle which of the following is completely polarized?
A Reflected light
B Refracted light
C Both reflected and refracted light
D Neither reflected nor refracted light

23-Signal from a remote control to the device operated by it travels with the speed of
A Sound
B Light
C Ultrasonic
D Supersonic

24-In Young's double slit experiment on interference, the ratio of the intensities of a bright and a dark band is 6:1. The ratio of the amplitudes of the interfering waves is
A 16
B 5/3
C 4
D 1/4


25-In a spectrometer experiment, monochromatic light is incident normally on a diffraction grating having 4.5 x 10^5 lines per meter. The second order line is seen at an angle of 30 degrees to the normal. What is the wavelength of the light?
A 200 nm
B 430 nm
C 500 nm
D 556 nm

26-A light of wavelength lambda is incident on a diffraction grating on which the slit spacing is equal to 3 lambdas. What is the sine of the angle between the second order maximum and the normal?
A 1/6
B 1/3
C 2/3
D 1

27-Which of the following frequency ranges includes most of the electromagnetic waves emitted by the ultra-violet tubes used in a sun bed?
A 5 x 10^5 to 5 x 10^8 Hz
B 5 x 10^8 to 5 x 10^11 Hz
C 5 x 10^11 to 5 x 10^14 Hz
D 5 x 10^14 to 5 x 10^17 Hz

29-Ultra-violet rays differ from X-rays in that ultra-violet rays
A Cannot be diffrated
B Cannot be polaarized
C Do not affect a photographic plate
D Have a lower frequency

29-The meter was defined in terms of the wavelength lambda of the orange spectral line emitted by excited atoms of Krypton-86. Thus 1 meter=n.lambda, where n is the number of wavelengths in a meter of vacuum. What is the best value for n
A 1.43 x 10^4
B 1.65 x 10^6
C 2.00 x 10^8
D 3.33 x 10^12


30-Which of the following gives three regions of the electromagnetic spectrum in order of increasing wavelength?
A Gamma rays, microwaves, visible radiation
B Radio waves, ultraviolet, x-rays
C Ultraviolet, infrared, microwaves
D Visible radiation, gamma rays, radio waves


UHS MBBS and BDS Expected Merit 2016

Here is the Expected Merit of Open Merit of Punjab Public Sector Medical Colleges for the Year 2016.About 56,000 people appeared for MCAT.And about 1100 plus were successful in securing 1000 plus marks.The statistics are quite startling and have pushed the panic button of students.Many People are predicting that merit will be 87 plus.They may be correct.But if we look back,we will find  that this story of  high merit is told every year.And when the first list comes merit is lower than expected and eventually after second and third merit list many of the aspiring students get admission.

MBBS Expected Merit 2016 :

Sr.No.Medical CollegeFirst Merit listLast Merit List
1.King Edward Medical University, Lahore91.491+
2.Allama Iqbal Medical College, Lahore90.289.8
3.Services Institute of Medical Sciences, Lahore89.489.0

Fatima Jinnah Medical College, Lahore

Sheikh Khalifa Bin Zayed Al-Nahyan Medical & Dental College, Lahore 


6.Nishtar Medical College, Multan
7.Ameer-ud-Din Medical College, Lahore88.288.0
8.Rawalpindi Medical College, Rawalpindi87.887.5
9.Punjab Medical College, Faisalabad87.887.5
10.Quaid-e-Azam Medical College, Bahawalpur87.687.3
11.Sargodha Medical College, Sargodha87.487.2
12.Gujranwala Medical College, Gujranwala87.487.2
13.Nawaz Sharif Medical College, Gujrat87.186.9
14.Sahiwal Medical College, Sahiwal87.086.8
15.Sheikh Zayed Medical College, Rahim Yar Khan86.986.8
16.Khawaja Mohammad Safdar Medical College, Sialkot86.886.7
17.D.G. Khan Medical College, D.G. Khan86.786.6

BDS Expected Merit 2016 : 

1.                                 2.

de' Montmorency College of Dentistry, Lahore

Nishtar Institute of Dentistry, Multan

Dental Section, Punjab Medical College, Faisalabad




Expected closing Merit of MBBS is 86.6.But who knows it can drop to 86.5 as well.Furthermore,expected closing merit of BDS and reciprocal is 86.4.
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