For the same metal the Δ f H 0 for fluoride to iodide, negative value, numerically
For a system at 300 K, change in enthalpy is 40 kJ . mol – 1 and change in entropy is 200 J . K – 1 . mol – 1 . Gibbs free energy of the system at that temperature will be
The heat of combustion of carbon to C O 2 is -393.5 kJ/mol. The heat released upon formation of 35.2 g of C O 2 from carbon and oxygen gas is
The enthalpy is maximum for
For which of the following reaction, ∆ H = ∆ E + 2 RT ?
Internal energy is a function of
The enthalpies of formation of an the element in its standard states is
A system absorbs 600J of energy and does work equivalent to 400J of energy. The internal energy change is
The enthalphy change for the process, I 2 s I 2 g , ∆ H = + x kJ is called enthalpy of
The work done when 65.38g of zinc dissolved completely in HCl in an open beaker at 300k is
A gas absorbs 500J heat and utilized QJ in doing work against an external pressure of 2 atm. If ΔE is -510 J, values of ΔV and W respectively are
The internal energy change when a system goes from state A to B is 40 KJ/mole. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy ?
Entropy of a system depends upon
Molar heat capacity of water in equilibrium with the ice at constant pressure is:
A spontaneous process is defined as a process
For a gas having molar mass M, specific heat at constant pressure can be given as:
Which one of the following is not a state function ?
What is the correct inference that can be drawn by dividing the vessel containing certain gas into equal parts
At 27 0 c , one mole of an ideal gas is compressed isothermally and reversibly from a pressure of 2 atm to 10 atm. The value of ∆ E and W are
When one mole of manganese is burnt completely to form Mn 3 O 4(s) at standard state conditions, the amount of heat liberated is
Given that the data for neutralization of a weak acid (HA) and strong acid with a strong base is : HA + OH – → A – + H 2 O; ΔH = – 41.80kJ H + + OH – → H 2 O; ΔH = – 55.90kJ The enthalpy of dissociation of weak acid would be
D 2(g) +1/2 O 2(g) → D 2 O (l) , Δ H= -294 KJ. If bond enthalpies of D 2 and O 2 respectively are 440 and 498 KJ/mole, then bond enthalpy of D-O is (KJ)
ΔH f of BaCO 3(s) , CO 2(g) , HCl (aq) and H 2 O (l) respectively are –1216, – 393, – 176 and – 286 KJ/mol. Then ΔH f of BaCl 2(aq) from BaCO 3(s) + 2HCl (aq) → BaCl 2(aq) + CO 2(g) + H 2 O (l) , ΔH = – QKJ
ΔH f of C 2 H 2 , C 2 H 4 and C 2 H 6 respectively are +226, +56 and -84 kJ/mole. The difference between heats of hydrogenation of ethyne and ethene forming ethane is (in kilo joules)
ΔS sur for H 2 +1/2O 2 H 2 O, ΔH= – 280 KJ at 400 K is
ΔS for vapourization of 900 g water (in KJ/ K) is [ ΔH vap =40KJ/mol]
Which one of the following reaction involves in decrease of entropy
If S 0 of Al, Cl 2 and AlCl 3 respectively are 28.3, 223 and 110 J/mol/K ΔS 0 for 2Al + 3Cl 2 → 2AlCl 3 [in J/K]
Statement I: Heat of neutralization of HClO 4 with NaOH is same as that of HCl with NaOH. Statement II: Both HCl and HClO 4 are strong acids.
ΔH 0 and ΔS 0 for P 4(s) +5O 2(g) → P 4 O 10(s) respectively are – 2984 KJ and – 838J. ΔG 0 value is (in kilo joules) nearly
Statement I : Entropy of a perfect crystalline substance at absolute zero is zero. Statement II : At absolute zero, translational kinetic energy of a system is zero.
Statement I: Heat of sublimation is the sum of heat of fusion and heat of vaporisation. Statement II : Heat of the reaction or enthalpy change is same whether reaction takes place in one step or in multiple steps.
At 60 ° c ,one mole of dinitrogen tetroxide is fifty percent dissociated N 2 O 4 ⇌ 2 NO 2 . the standard free energy change at this temperature and at 1atm. (log 1.33 = 0.1239)
Statement I : Absolute value of entropy cannot be determined. Statement II : Internal energy is an intensive property.
A system liberates 400 Joules of heat and does 600 Joules of work. Change in internal energy for the process is
Enthalpy of vapourization of a liquid is 54.4 kJ/mole. Entropy of vapourization of liquid will be ( Boiling point of liquid = 222 0 c )
Out of internal energy (I), boiling point (II), pH (III) and E.M.E of the cell (IV) intensive properties are :
One mole of an ideal gas at 25’c expands in volume from 1.0L to 4.0L at constant temperature .what work (in J) is done if the gas expands against vacuum (P external =0)?
2 mole of zinc is dissolved in HCI at 25 o ‘C. The work done in open vessel is
For a process to be spontaneous at constant T and p
The bond dissociation energies of X 2 , Y 2 and XY are in the ratio of 1 : 0 . 5 : 1 . ΔH for the formation of XY is – 200 kJ mol – 1 . The bond dissociation energy of X 2 will be
Which one of the following represents a set of intensive properties
Thermodynamic functions are classified as state and path functions. Which one of the following is not a state function
Enthalpy of formation of A 2 B is +1000 KJ. Ratio of bond enthalpies of A 2 , B 2 and A 2 B is 1 : 2 : 1. Bond enthalpy of B 2 would be
For the reaction, X 2 O 4 ( l ) ⟶ 2 XO 2 ( g ) Δ U = 2 . 1 kcal , Δ S = 20 calK – 1 at 300 K Hence, Δ G is
Essential condition for a process to be spontaneous is A) Δ S s y s = + v e B) Δ H s y s = − v e C) Δ G s y s = − v e D) Δ S t o t a l = + v e
Standard enthalpies of formation of CO 2 , H 2 O and C 2 H 4 are -396 kJ/mole – 288 kJ/mole and +52 kJ/ mole respectively. Enthalpy of combustion of Ethene is
Which of the following statements is correct for a reversible process in a state of equilibrium?
N – N single bond enthalpy is “X”. N = N double bond enthalpy is “Y”. Correct relation is
Statement I : Bond length in C–C > N–N > O–O Statement II : Bond enthalpy in C–C > N–N > O–O
The correct option for free expansion of an ideal gas under adiabatic condition is :
For a given reaction, Δ H = 35.5 kJ mol − 1 and Δ S = 83.6 JK − 1 mol − 1 The reaction is spontaneous at(Assume that Δ H and Δ S do not vary with temperature.)
For free expansion of an ideal gas adiabatically , the correct option is
Enthalpies of combustion of carbon, Hydrogen, and benzene are -94kcal/mole, – 68kcal/mole and -780kcal/mole respectively. Enthalpy of formation of benzene is
For the reaction 2 H g H 2 g , the correct relation is
Δ f H of H 2 O l is –286 kJ / mole and Δ f H of H 2 O g is –246 kJ / mole, then the enthalpy change when 9 grams of water vapour condenses liquid water is
The reaction in which ΔH = ΔE is
Given 1 2 A B + q 1 ; 2 B C − q 2 ; where q 1 and q 2 are the heat changes during the Process. The heat change for the process C A will be
Neutralization is the reaction between acid and base.It is highly exothermic.Enthalpy of neutralization is least for the reaction
A s + 20 moles H 2 O A in 20 moles H 2 O ; ΔH = − 72 kJ A s + 40 moles H 2 O A in 40 moles H 2 O ; ΔH = − 81 kJ Enthapy of dilution when a solution containing one mole of A in 20 moles H 2 O is diluted by adding 20 moles of H 2 O to it will be
For the same change in volume of fixed amount of perfect gas, reversible work of expansion is maximum at
Mean bond enthalpy of C – H in CH 4 is X Kj / mole .Heat of Atomization of CH 4 is Y Kj / mole . Correct relation is
A system which can exchange energy with the surroundings but not matter is called
Which of the following statement is false?
Which is an extensive property of the system?
Which among the followign is an intensive property?
A gas abosorbs 400 J of heat and expands by 2 × 10 -3 m 3 against a constant pressure of 10 5 Nm -2 . The change in internal energy is
The reaction which shows standard heat of formation of water correctly is
An ideal gas occupying a volume of 2 dm 3 and a pressure of 5 bar undergoes isothermal and irreversible expansion against external pressure of 1 bar. The final volume of the system and the work involved in the process is
An ideal gas is taken through the cycle A B C A as shown in figure. If net heat supplied to the gas in the cycle is 5J, the work done by the gas in the process C A is
The dissociation energy of CH 4 is 400K.Cal mol -1 and that of ethane is 670K.Cal mol -1 . The C-C bond energy is
Heat capacity of water is 18 cal-degree -1 -mol -1 . The quantity of heat needed to rise temperature of 18g water by 0.2 o C is X cal. Then amount of CH 4 (g) to be burnt to produce X cal heat is (CH 4 +2O 2 →CO 2 +2H 2 O, ΔH= –200K.Cal)
A process is spontaneous at all temperatures when
Heat capacity (C V ) of an ideal gas is X KJ/ mole/K. To rise its temperature from 298 K to 318 K, heat to be supplied per 10g gas will be (in KJ) [MW =16]
A gas absorbs 250 J of heat and expands from 1 litre to 10 litre at constant temperature against external pressure of 0.5 atm. The values of q, w and Δ E will be respectively.
When 9.2g ethanol was burnt in bomb calorimeter in excess of oxygen 320 kJ heat is liberated. Heat of combustion of ethanol at constant volume and temperature (in kJ) is
The heat of combustion of solid benzoic acid at constant volume is – 321.30 KJ at 27 0 C. The heat of combustion at constant pressure is
The gas constant R represents work done
Heat of combustion of benzoic acid at constant volume and 298 K is –3233kJ/mole. When 0.5g of benzoic acid is burnt in bomb calorimeter, the temperature of calorimeter increased by 0 . 53 0 c . Now in the same bomb calorimeter when 1g of ethane is burnt then temperature increased by 2 . 04 0 c . ΔH for combustion of ethane is
Calculate ΔH o for the reaction : Na 2 O + SO 3 → Na 2 SO 4 given the following : A) Na (s) + H 2 O (l) → NaOH (s) + 1/2 H 2(g) ; ΔH o = – 146 kJ B) Na 2 SO 4(s) +H 2 O → 2NaOH (s) + SO 3(g) ; ΔH o = + 418 kJ C) 2 Na 2 O (s) + 2H 2(g) → 4Na (s) + 2H 2 O (l) ; ΔH o = + 259 kJ
ΔS for 4Fe (s) +3O 2(g) →2Fe 2 O 3(s) is – 550 J/mol/K. The process is found to be spontaneous even at 298K because [ Δ H = –1650 kJ]
For a certain reaction, ΔH 0 and ΔS 0 respectively are 400 KJ & 200 J/mol/K. The process is non-spontaneous at
Enthalpy of vapourisation for water is 186.5kJ mol –1 . The entropy change during vapourisation is kJK –1 mol –1
∆ f 0 S of H 2 O (l) , NH 3(g) and NO (g) respectively are –237, –108 and +104 K.Cal.mole –1 . Then ∆ f 0 S for 4NH 3(g) + 5O 2 4NO (g) + 6H 2 O (in K.Cal) will be
G 0 of graphite and diamond respectively are zero and 2.9 kJ/mole. Gibbs energy change for producing 24g diamond from graphite in kilo joules is
For a reaction the ΔS value is -20Jmol –1 k -1 . If the temperature is increased from 0°C to 25°C, the increase in the value of ΔG is (in J mol –1 ) (Hint : use ΔG = ΔH –T ΔS)
Statement I: The enthalpy of formation of H 2 O (l) is greater than that of H 2 O (g) . Statement II: Enthalpy change is negative for the condensation reaction H 2 O (g) → H 2 O (l) .
Statement I: Mass and volume are extensive properties. Statement II : Mass / volume is also an extensive property.
Enthalpy of formation of OH – in aqueous solution is
Benzene burns in oxygen according to the equation 2C 6 H 6(I) +15O 2(g) 12CO 2(g) + 6H 2 O (l) . How many litres of oxygen are required at STP for the complete combustion of 39 g of liquid benzene?
Statement I ; Standard enthalpy of monoclinic sulphur is zero Statement II ; Internal energy is an intensive property
Δ f 0 H is positive for the compound
Out of molar entropy (I), specific volume (II), heat capacity (III), volume (IV), extensive properties are :
Thermodynamic equilibrium involves
For the reaction PCl 5 ( g ) ⟶ PCl 3 ( g ) + Cl 2 ( g )
For the reaction 2 H ( g ) ⟶ H 2 ( g ) , the sign of ΔH and ΔS respectively are
For a reaction to occur spontaneously
The free energy change ∆ G=0, when
which of the following conditions will always lead to a non-spontaneous change?
The enthalpy change for a reaction does not depend upon
A hydrocarbon contains 81.8% by weight of carbon. Empirical formula of the hydrocarbon is
A 2 g + B 2 s 2 AB g ; ΔH = + 54 kJ A 2 g + B 2 g 2 AB g ; ΔH = − 9 kJ From the given data, Enthalpy of sublimation of ” B 2 ” is
Lattice enthalpy of ‘AB(s)’ is equal to 90 Kcal/mole. Magnitude of hydration enthalpies of A + and B – are 63 Kcal/mole and 45 Kcal/mole respectively. Enthalpy of solution of ‘AB’ will be
A) Enthalpy of atomization B) Enthalpy of fusion C) Enthalpy of solution D) Enthalpy of condensation E) Enthalpy of formation From the above list identify how many always have the Enthalpy change to be positive
For a particular process when ΔH = 60 kJ / mole and Δ S=200J Kmole − 1 then the process is non-spontaneous at
Which one of the following represents standard enthlpy of formation
Na s Na g , ΔH = + 108 kJ . ∆ H in this process cannot be called as
At 298K a gas in state ‘A’ (P = 20 atm, V = 1 l) changes to state ‘B’ (P = 2atm, V = 10 l). Workdone if carried out reversibly is
In which of the following process, increase in Entropy is observed
A system absorbs 200 J of heat and 700 J of work is done by the system. Change in internal energy for the process is
The thermodynamic property whose absolute value can be determined is
Consider the thermochemical equation, C 2 H 5 OH l + 3 O 2 g 2 CO 2 g + 3 H 2 O l , difference between ΔH and Δ U ∆ H – ∆ U of the reaction at ‘T’ kelvin is
The correct thermodynamic conditions for the spontaneous reaction at all temperatures is
A process can be Exothermic or Endothermic. Exothermic process of the following is
Under isothermal conditions, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is [Given that 1 L bar =100 J]
In which case change in entropy is negative?
When 5 litres of a gas mixture of methane and propane is perfectly combusted at 0 ° C and 1 atmosphere, 16 litres of oxygen at the same temperature and pressure is consumed. The amount of heat released from this combustion in kJ ΔH comb. CH 4 = 890 kJ mol – 1 , ΔH comb. C 3 H 8 = 2220 kJ mol – 1 is
Three thermochemical equations are given below ( i ) C ( graphite ) + O 2 ( g ) CO 2 ( g ) ; Δ r H ° = x kJ mol – 1 ( ii ) C ( graphite) + 1 / 2 O 2 ( g ) CO ( g ) ; Δ r H ° = y kJ mol – 1 ( iii ) CO ( g ) + 1 / 2 O 2 ( g ) CO 2 ( g ) ; Δ r H ° = z kJ mol – 1 Based on the above equations, find out which of the relationship given below is correct.
For a sample of perfect gas when its pressure is changed isothermally from p i to p f , the entropy change is given by
For the reaction, 2 Cl ( g ) Cl 2 ( g ) , the correct option is :
At standard conditions, if the change in the enthalpy for the following reaction is –109 kJ mol – 1 . H 2 ( g ) + Br 2 g 2 HBr ( g ) Given that bond energy of H 2 and Br 2 is 435 kJ mol – 1 and 192 kJ mol – 1 , respectively, what is the bond energy (in kJ mol – 1 ) of HBr?
If for a certain reaction ∆ r H is 30 kJ mol – 1 at 450 K, the value of ∆ r S (in JK – 1 mol – 1 ) for which the same reaction will be spontaneous at the same temperature is
A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy ∆ U of the gas in joules will be
An ideal gas expands isothermally from 10 – 3 m 3 to 10 – 2 m 3 at 300 K against a constant pressure of 10 5 Nm – 2 . The work done on the gas is
Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure. AB Isothermal expansion AC Adiabatic expansion Which of the following options is not correct?
Of the following, the largest value of entropy at 25°C and 1 atm is that of:
In a closed insulated container a liquid is stirred with a paddle to increase the temperature. Correct conditions are
Molar heat capacity of water at constant pressure is 75 JK − 1 mole − 1 . When 2 kJ of heat is provided to 200g of water which is free to expand, the increase in temperature is
Under isothermal and reversible conditions, the term ” free energy” in thermodynamics signifies :
Enthalpy of vapourization of liquid at 127° c is 50kJ/mole. Change in Internal energy during this process would be
Under isothermal conditions at 300K, a gas is expanded from 0.2 lit to 0.65 lit against a constant external pressure of 4 bar. Work done during the process is (1lit bar = 100J)
Bond enthalpies of H 2 , O 2 are 436kJ/mole and 498kJ/mole respectively. Calculate O–H bond enthalpy if Δ f H 0 of water is –286kJ/mole
An ideal gas is allowed to expand in a well insulated container against a constant external pressure of 5 atm from an initial volume of 8 litres to final volume of 10litres. Change in internal energy is
Wrong match about thermodynamic properties among the following is
Entropy is a very important thermodynamic property. Change in entropy is positive in the following process
For the reaction, X Y , ΔH = − 36 kJ / mole ; ΔS = − 90 Jk − 1 mole − 1 the reaction is spontaneous ( ΔH & ΔS do not vary with temperature) at
Correct expression to calculate reversible isothermal work of expansion is
Statement–I: Standard enthalpy of compound is equal to its standard enthalpy of formation. Statement–II: T Δ S system is the energy not available to do useful work.
Neutralization reactions are exothermic. Enthalpy of neutralization is highest for
A system absorbs 900J of heat from the surroundings and does a work of 450J. Change in internal energy during the process is
Statement–I: Enthalpy of monoclinic sulphur is zero. Statement–II: ∆ G system is the energy not available to do useful work.
Enthalpy is the heat content of the system at constant pressure. Standard enthalpy is zero for
How many of the following thermodynamic properties are classied as intensive property and also as a state function ; A) Temperature ; B) Enthalpy ; C) Internal energy ; D) Work ;
At 27 0 c for the reaction, CaCO 3 s ⇌ CaO s + CO 2 g , ∆ H – ∆ E will be
Enthalpy of combustion of diamond is 395kJ/mole and Enthalpy of combustion of graphite is 393kJ/mole. Enthalpy change when one mole of diamond converts to one mole of graphite is
In which of the following process , Enthalpy change cannot be called as Enthalpy of atomization
A well stoppered thermos flask contains some ice cubes. This is an example of
The intensive property among the following given quantities
In which of the following sets, all the properties belong to same category (all extensive or all intensive)?
Which of the following statements is correct
For a given substance, internal energy will be maximum when it is in
Which of the following holds good to the laws of thermodynamics for the reaction? C 2 H 4(g) + 3O 2 (g) 2CO 2(g) +2H 2 0 (l)
During expansion of a gas into vaccum (P ext = 0), work done is zero if the process is A) Reversible B) Irreversible C) Isothermal
For the reaction involving the complete combustion of isobutane, the correct relation is
Correct statements about internal energy are A) The absolute value of internal energy cannot be determined B) The internal energy of one mole of a substance is same at any temperature C) The measurement of heat change during a reaction by bomb calorimeter is equal to internal energy change D) Internal energy is an extensive propriety
Mathematical form of 1st law
The enthalpy of the reaction, H 2 g + 1 2 O 2 g H 2 O g , ∆ H 1 and that of H 2 g + 1 2 O 2 H 2 O l , ∆ H 2 . Then the correct between the magnitude of ∆ H 1 and ∆ H 2 is
The enthalpy of elements in their standard states is taken as zero. Hence the enthalpy of formation of a compound is
Extensive property is a property whose value depends on the quantity or size of matter present in the system. Those properties which do not depend on the quantity or size or matter present are known as intensive properties. Find out the correct match
The following reaction is not a combustion reaction
During a process, work equivalent to 400J is done on a system, which gives out of 125J of heat energy. The change in internal energy is
Which of the following is not a correct statement
The heat change for the following reaction, C graphite + 1 4 S 8 α CS 2 l is known as
An ideal gas expands in volume from 1 × 10 -3 m 3 to 1×10 -2 m 3 at 300 K against a constant pressure at 1 × 10 5 Nm -2 . The work done is
One mole of an ideal gas at 300 K is expanded isothermally reversibly from an initial volume of 1 litre to 10 liters. The ΔE for this process is (R=2 cal mol –1 K –1 )
A system absorbs 10 KJ of heat at constant volume and its temperature rises from 27 0 C to 37 0 C. The ΔE of reaction is
The molar heat capacity of water at constant pressure, C, is 75 JK –1 mol –1 . When 1.0KJ of heat is supplied to 100g of water which is free to expand, the increase in temperature of water is
Latent heat of vapourisation of a liquid at 500 K and 1atm pressure is 10 K.Cal/mole. What is the change in internal energy when 3 mole liquid vapourised at the same temperature will be
Incorrect statement related to an irreversible process is
For the reaction Then choose the correct statements from the following a) The process is spontaneous at all temperatures b) The process is accompained by an increase entropy c) The process is accompained by a decrease in entropy d) The process is accompained by a decrease in enthalpy The correct statements are
For which of the following elements, the standard enthalpy is not zero?
For a reaction R 1 , For a reaction R 2 , Reaction R 1 is non-spontaneous but along with R 2 it is spontaneous. This means that
In which of the following conditions, increase in internal energy ( ΔE > 0) is maximum ?
The volume of gas is reduced to half of its original volume. The specific heat of gas will ….
Change in enthalpy when 11.2 dm 3 of He at NTP is heated in a cylinder to 100 0 C is (assume ideal behaviour)(Hint : ΔH = nCpΔT, for mono atomic gas C P = 5/2R)
Heat of combustion of C 2 H 4 is -337 K.Cal. If 5.6 lit O 2 is used at STP in the combustion, heat liberated is …… K.Cal
Human body requires 2370 K. Cal of energy daily. The heat of combustion of glucose is –790 K.cal/mole. The amount of glucose required for daily consumption is
The heats of combustion of ethane, ethene and acetylene are -341.1, -330 and –310.9 K.Calmol –1 respectively. The best fuel among them is
For a particular reversible reaction at temperature T, ∆ H and ∆ S were found to be both positive. If T e is the temperature at equilibrium, the reaction would be spontaneous when
The heat of combustion of benzene at 27 0 c in a bomb calorimeter i.e. for the reaction C 6 H 6 l + 15 2 O 2 g 6 CO 2 g + 3 H 2 O l , is -780 K.Cal/mole. The heat evolved on burning 39g of benzene in an open vessel wil be
N 2 + 3H 2 → 2NH 3 ;ΔH = -46K.Cals. From the above reaction, heat of formation of ammonia is
For the reaction 2H 2 O (l) →H 3 O + (aq) + OH – (aq) , the value of ΔH is
Heat liberated in the neutralisation of 500 ml of 1N HCl and 500 ml of 1N NH 4 OH is 1.36 K.Cals. The heat of ionisation of NH 4 OH is(Heat of neutralization of strong acid vs strong base is -13.7 Kcals/mole)
When 1 litre of 1M HCl is mixed with 1 litre of 1M NaOH, the rise in temperature was found to be T 1 . In another experiment 1 litre of 0.5 M NaOH is mixed with 1 lit. of 0.5 M HCl. The rise in temperature was found to be T 2 . Then
Heat of neutralisation for the reaction NaOH+HCl → NaCl+H 2 O is -57.1 K.J. mole -1 . The heat released when 0.25 moles of NaOH is treated with 0.25 moles of HCl is
The heat of atomisation of PH 3(g) is 228 K.Cal mol –1 and that of P 2 H 4(g) is 355 K.Cal mol –1 The energy of the P–P bond is (in K.Cal);
ΔH 0 f for Cl – (aq) is
Work done during the combustion of one mole of CH 4 in bomb calorimeter is
The dissociation energy of CH 4 is 400K.Cal mol –1 and that of ethane is 670 K.Cal mol –1 . The C–C bond energy is:
Then ΔH for HCN aq +NH 4 OH aq → Products (in KJ)
P 4(g) → P 4(s) , ΔH=-59 KJ; P 4(g) +5O 2 (g) → P 4 O 10(s) , ΔH = ? [ ΔH f (P 4 O 10 ) = -2984 KJ]
Given C (s) + O 2(g) → CO 2(g) ; ΔH = – 395 KJ S (s) + O 2(g) → SO 2(g) ; ΔH = – 295 KJ CS 2(l) +3O 2(g) → CO 2(g) + 2SO 2(g) ; ΔH = – 1110 KJ The heat of foramation of CS 2(l) is
1) C Graphite + O 2(g) CO 2(g) ;ΔH = -94 K.Cals 2) C Diamond + O 2(g) CO 2(g) ;ΔH = -94.5 K.Cals From the above data the heat of transition of C diamond C Graphite
Δ H of combustion of yellow P and red P are –11K.J and –9.78 K.J respectively ΔH of transition of yellow P to Red P is
How much energy is released when 6 mole of octane is burnt in ? Given ∆ H f 0 for CO 2(g) , H 2 O (g) and C 8 H 18(l) respectively are -390, -240 and +160 KJ/mol
Given C + 2S → CS 2 , =+117.0 kJ mol –1 C + O 2 → CO 2 , = – 393.0 kJmol–1 S + O 2 → SO 2 , = – 297.0 kJmol–1 The heat of combustion of CS 2 + 3O 2 → CO 2 + 2SO 2 is
The lattice energy of solid NaCl is 180 K.Cal per mol. The dissolution of the solid in water in the form of ions is endothermic to the extent of 1K.Cal per mol. If the solvation energies of Na + and Cl – ions are in ratio 6:5, what is the enthalpy of hydration of sodium ion?
Cl (g) + e – Cl – (g) , EA=-348 KJ/mol at 0 K. then ΔH for same process at 300K (in KJ) [R=8x 10 -3 J/mol/K] :
For the reaction, 2 H 2 + O 2 2 H 2 O , : ΔH = – 571kJ ; Bond energy of (H–H) = 435 kJ and (O=O) =498kJ , the average bond energy of O–H bond using the above data is
If the standard molar enthalpy of formation of CaO s , CO 2 g and CaCO 3 s is –635, –393 and –1207kJ mol –1 respectively, the ∆ r H in kJ/mole for the reaction, CaCO 3 s CaO s + CO 2 g is
Heat of formation of CO and CO 2 are –26.4,- 94.0 kcal/mole respectively. What is the heat of combustion of CO in kcals ?
N 2 + O 2 → 2NO, ΔH = + Q 1 N 2 + 2O 2 → N 2 O 4 , ΔH = – Q 2 NO + 1/2O 2 → NO 2 , ΔH = – Q 3 2NO 2 → N 2 O 4 , ΔH = – Q 4 , then
ΔH for S α → S β is + 0.32 KJ/ mole. Then, ΔH for 1/8S β + O 2(g) → SO 2(g) is [ Δ f H (SO 2 ) is -296 KJ/mole]
ΔH o for a reaction F 2 + 2HCl 2HF + Cl 2 is given as -352.8 KJ. ∆ H f 0 for HF is –268.3KJ mol -1 , then ∆ H f 0 of HCl would be
∆ H C ≡ O , ∆ H O = O , ∆ H C = O respectively are 1070, 498 and 741KJ/mol. Then ΔH for CO + 1 2 O 2 CO 2 [in KJ] is
The enthalpies of formation of HCl , NaOH , NaCl and H 2 O are –120, –82, –148 and –68 K.Cals/mole. respectively. ΔH of the following reaction is HCl + NaOH NaOH + H 2 O is
The heats of combustion of carbon, hydrogen and acetylene are –394K.J, – 286K.J and –1301 K.J respectively. Calculate heat of formation of C 2 H 2
What is the heat of formation of C 6 H 6 , given that the heats of combustion of benzene, carbon and hydrogen are 782, 94 and 68K. Cal respectively ?
Calculate the heat of formation of KOH from the following data in K.Cal. K (s) + H 2 O + aq → KOH (aq) +1/2 H 2 ; ΔH = -48.4K.Cal H 2(g) + 1/2O 2(g) → H 2 O (l) ; ΔH = -68.44K.Cal KOH (s) + aq → KOH (aq) ; ΔH = -14.01K.Cal
Consider, N 2 + 2 O 2 2 NO 2 + X kJ ; 2 NO + O 2 2 NO 2 – Y kJ ; Enthalpy of formation of NO in kJ will be
For the process 4OH – (aq) 2H 2 O (l) + O 2(g) + 4e – taking place at 298K at anode, ΔH is [ Δ f H of H 2 O (l) and OH – (aq) are –286 and –230 KJmol -1 ]
If S + O 2 → SO 2 ; ΔH = – 398.2 KJ SO 2 + 1/2O 2 → SO 3 ; ΔH = – 98.7 KJ SO 3 + H 2 O → H 2 SO 4 ; ΔH = – 130.2 KJ H 2 + 1/2O 2 → H 2 O ; ΔH = – 227.3 KJ The enthalpy of formation of sulphuric acid at 298 K will be
If the heats of formation of Al 2 O 3 and Fe 2 O 3 are -400 K.Cal and -190 K.Cal respectively, the heat of the following reaction is 2Al + Fe 2 O 3 →2Fe + Al 2 O 3
C 6 H 6 + 3 H 2 ⇌ C 6 H 12 , ∆ H = – 204 kJ ; Heat of hydrogenation of each C=C (assumed to be) in benzene is [in KJ]
Given that S (s) + 3 2 O 2(g) SO 3(g) + 2xK.Cal . SO 2 (g) + 1 2 O 2(g) SO 3(g) + yK.Cal . The enthalpy of formation SO 2 will be
If the standard molar enthalpy of formation of SO 2(g) and SO 3(g) is – 296.82kJ mol –1 and – 395.72 kJ mol –1 respectively, the heat of reaction in kJ mol –1 , for SO 2(g) + 1/2 O 2(g) SO 3(g) , is
If the bond energies of H–H, Br-Br and H-Br are 433, 192 and 364 kJ mol –1 respectively, then ΔH 0 for the reaction : H 2(g) + Br 2(g) → 2HBr (g) is
ΔG 0 of Cu + (aq) and Cu 2+ aq respectively are +50 and +66 kJ/mole. Value of (ΔH 0 –TΔS 0 ) for Cu + aq → Cu 2+ aq in kilo joules is
The correct order of ∆ 0 G values of the processes at the same temperature is
One mole of ice is converted in to water at 273K. The entropies of H 2 O (s) and H 2 O (l) are 38.20 and 60.01 J mole -1 K -1 respectively. The enthalpy change for this conversion is
; ; , Then the absolute entropy change of is
The entropy value at temperature T is
In the vicinity of absolute zero, the value of Cp- Cv is
CaCO 3 → CaO+CO 2 , ΔH= + 180KJ. If entropies of CaCO 3 , CaO & CO 2 respectively are 93, 39 and 213 J/mol/K, then ΔS (total) [in J/K] at 300 K is :
At 0 0 C ice and water are in equilibrium and ΔH = 6.0kJ, then ΔS will be
For a reaction to be spontaneous at all temperatures
The melting point of a solid is 300 K and its latent heat of fusion is 600 cal mol-1. The entropy change for the fusion of 1 mole of the solid (in cal K-1 ) at the same temperature would be :
Statement I: Enthalpy of graphite is lower than that of diamond. Statement II : Entropy of graphite is greater than that of diamond.
Statement I: For a process to be spontaneous, the change in free energy must be negative. Statement II : The change in entropy for a process must always be positive if it is spontaneous.
Statement I: Many endothermic reactions that are not spontaneous at room temperature become spontaneous at high temperature. Statement II : Entropy of the system increases with increase in temperature.
Statement I : For a reaction 2NH 3(g) → N 2(g) + 3H 2(g) ; ΔH > ΔE . Statement II : Enthalpy change is always greater than internal energy change.
Statement I: For an isothermal reversible process, q = – w i.e. work done by the system equals the heat absorbed by the system. Statement II : Enthalpy change (ΔH) is zero for isothermal process.
Which of the following reaction is spontaneous at room temperature
Select the incorrect relation
Which of the following situation will need low temperature for a reaction become spontaneous?
Which of the following situation will need high temperature for a reaction to become spontaneous?
For the reaction 2A B; ∆ H = +45 kJ/mole at 27°C. The entropy values of A and B at 27°C are 90 J K – 1 mole – 1 and 300 J K – 1 mole – 1 . Free energy change for the reaction is and the nature of reaction is .
One mole of an ideal gas is expanded reversibly and isothermally from 1 litre to 10 litre at 300K. Correct relation among the following is
Enthalpy of trimerization of ethyne to benzene is ‘-X’ kJ. Enthalpy of hydrogenation of benzene is ‘-Y’ kJ. Enthalpy change for the formation of one mole of cyclohexane from ethyne would be
Consider the process, 2 A ( s ) + B 2 ( g ) 2 AB ( g ) , ∆ H = – 342 kJ . Equilibrium temperature of the process is 603K. The process is
Which of the following statement about thermochemistry is false?
Enthalpy change for the reaction 4 H g 2 H 2 g , is -869.6 kJ. The dissociation energy of H — H bond is
Molar enthalpy change for vapourisation of 1 mole of water at 1 bar and 100 ° c is 41KJ mol -1 . Calculate the internal energy change, when 1 mole of water is vaporised at 1bar pressure and 100 ° c .
Thermodynamically most stable allotrope of carbon is
Consider the equation, C graphite + O 2 g CO 2 g , ∆ H = – 394 kJ / mole ; Incorrect statement about the reaction is
Standard enthalpies of formation carbon dioxide, water and acetylene are – 390 , – 286 and + 254 kJ / mole respectively. Enthalpy of combustion of acetylene is equal to…..kJ/mole
For the reaction A s + 2 B g C g + 3 D l , the value of ∆ H – ∆ E at 300 K will be
A chemical process involves decrease in enthalpy and decrease in entropy. If the magnitude of change in enthalpy is 1000 times the change in entropy, the process is spontaneous at
The relation between ∆ U and W during an adiabatic change in an Ideal gas
The bond enthalpy values of H-H, O=O bonds are 436 kJ/mole and 498 kJ/mole respectively. Standard enthalpy of formation of water is -286 kJ/mole. The bond enthalpy of O-H bond is equal to—–kJ/mole
Bond enthalpies of P-P, O=O and P-O are p, q and s respectively. Enthalpy change for the process, P 4 +3O 2 P 4 O 6 is
A system absorbs 800 joules of energy and does of work of 200 joules change in internal energy of the process is
Enthalpy of combustion of Rhombic sulphur is -2400 kJ/mole. Enthalpy os formation sulphur dioxide is
Statement-I : For the same amount of heat absorbed reversibly and isothermally, the increase in randomness at low temperature is more than at higher temperature. Statement-II : ΔS system for a spontaneous process is always positive.
Air contains 20% O 2 by volume. How much volume of air will be required for combustion of 100 cc of acetylene?
Thermodynamics is based on
In thermodynamics, the part of universe in which observations are made and remaining universe are respectively called
Select the correct statement about the system.
Which of the following variables are called state variables?
On which of the following factor(s) does the internal energy of the system depend?
In thermodynamics, the sum of all energy of the system, is called
A system containing some quantity of water in a thermos flask or in an insulated beaker. This would not allow exchange of heat between the system and surrounding through its boundary. The process applied on the system is called
An adiabatic process occurs in
Which of the following property of a system can be changed by transfer of heat from the surrounding to the system or vice-versa without expenditure of work?
What is the change in the energy of system if 500 cal of heat energy are added to a system and system does 350 cal of work on the surroundings?
Which of the following is an extensive property?
For exothermic and endothermic reactions ∆ H will be respectively
Calculate the difference between C p and C V for l0 moles of an ideal gas.
Heat absorbed at constant volume is measured in a calorimeter in which steel vessel is immersed to ensure that
What is/are the uses of the enthalpy change?
For exothermic and endothermic reaction, the sign of q p respectively are
Hess’s law is based on
Which of the following properties is the measure of the degree of randomness or disorder in the system?
Lattice enthalpies are determined by
Entropy is
Statement 1 : ∆ H for an exothermic reaction is negative and for an endothermic reaction it is positive. Statement 2 : Enthalpy is an extensive property.
Choose the correct answer. A thermodynamic state function is a quantity
An ideal gaseous sample at initial state i (P o , V o , T o ) is allowed to expand to volume 2 V o using two different process; in the first process the equation of process is 2PV²=K 1 and in second process the equation of the process is PV= K 2 . Then,
What is the heat of hydrogenation of ethene if the bond energies of C- C, C = C, H-H, and C-H are 350, 600, 440 and 410 kJ/mole respectively?
If ∆ G for the reaction X + + Y − X 2 + + Y 2 − is Z, then the ∆ G for the reaction is 1 2 X + + 1 2 Y − 1 2 X 2 + + 1 2 Y 2 −
Calculate the change in entropy (ΔS), when one mole of an ideal gas is compressed to half of its initial volume and simultaneously heated to twice of its initial temperature.
A system absorbs and 200 Joules of heat and does 600 Joules of work. Change in internal energy for the process is
For a chemical process A B ; ∆ H = 45 KJ / mole and ∆ S = 15 JK – 1 mole – 1 . The process is spontaneous at
The process which is accompanied with decrease in entropy is
A system absorbs and 800 Joules of heat and does 600 Joules of work. Change in internal energy for the process is
Which one of the following is a false statement?
Thermodynamics deals with macroscopic properties.Internal energy is a very important Themodynamic property.Regarding internal energy , correct statement is
Regarding internal energy , correct statement is
For a system at 300 K, change in enthalpy is 60 kJ . mol – 1 and change in entropy is 200 J . K – 1 . mol – 1 . Gibbs free energy of the system at that temperature will be
How many of the following thermodynamic properties are classfied as extensive property and also as a state function ; A) Temperature ; B) Enthalpy ; C) Internal energy ; D) Work ;
For a system at 300 K, change in enthalpy is 60 kJ . mol – 1 and change in entropy is 300 J . K – 1 . mol – 1 . Gibbs free energy of the system at that temperature will be
Which one of the following enthalpy change will have positive sign only
Which of the following statement about thermochemistry is incorrect?
A system loses 600 J of heat to the surroundings and does a work of 900 J. Change in internal energy during the process is
At 27 o C for the combustion of two mole of benzene, ∆ H – ∆ E is equal to
Temperature of 1 mole of a gas is increased by 2 0 c at constant Pressure, work done is
The temperature of an ideal gas increases in an
For two mole of an ideal gas
For the reaction FeCO 3 ( s ) ⟶ FeO ( s ) + CO 2 ( g ) ; ΔH = 82 .8 kJ at 25 ∘ C what is ( ΔE or ΔU ) at 25″C?
The entropy change for a phase transformation is
Identify the correct statement regarding entropy
Consider the following reaction C 6 H 6 ( l ) + 15 2 O 2 ( g ) ⟶ 6 CO 2 ( g ) + 3 H 2 O ( g ) signs of Δ H , Δ S and Δ G for the above reaction will be
For the process H 2 O ( l ) ⇌ Equilibrium H 2 O ( s ) Select the correct option.
Which of the following conditions regarding a chemical process ensures its spontaneity at all temperature?
For isothermal expansion in case of an ideal gas
Given : C(diamond) +O 2 CO 2 ,; ∆ H =-395KJ C(graphite) + O 2 CO 2 ; ∆ H= 393KJ The enthalpy of formation of diamond from graphite is
Consider the following reactions C ( s ) + O 2 ( g ) ⟶ CO 2 ( g ) + xkJ CO ( g ) + 1 2 O 2 ( g ) ⟶ CO 2 ( g ) + ykJ The heat of formation of CO(g) is
If Δ f H ∘ C 2 H 4 and Δ f H ∘ C 2 H 6 areX 1 , and X 2 , kcalmol -1 , then heat of hydrogenation of C 2 H 4 is
What amount of energy (kJ) is released in the combustion of 5.8 g of C 4 H 10 (g)? 2 C 4 H 10 ( g ) + 13 O 2 ( g ) ⟶ 8 CO 2 ( g ) + 10 H 2 O ( l ) ; ΔH ∘ = − 5756 kJ
