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Subject: Chemistry, asked on 3/7/15

How​ΔS = Δq / T

Subject: Chemistry, asked on 12/6/15

An insulated container contains 1mole of a liqiud,molar volume 100ml at 1bar when the liquid is suddenly compressed to 100bar volume decreases to 99ml find deltaH and deltaU for the process

Subject: Chemistry, asked on 27/5/15

how can i know that a given reaction demonstrates enthalpy of reaction or enthalpy of combustion like this :
2CO(g) + O2(g) ---------> 2CO2 (g)
here the enthalpy change taking place is an example of enthalpy of reaction or enthalpy of combustion ??
as it involves oxygen then the entalpy change here should be enthaply of combustion , no ??
but the ans. is enthalpy of reaction .. plz explain how
also tell me that how can i differentiate between these two ??

Subject: Chemistry, asked on 26/5/15

As enthalpy of substance in their standard states is zero , then standard enthaply of reaction should also be zero for all substances (all are in standard states) , but it is not so .. why ?? explain

Subject: Chemistry, asked on 22/5/15

We have studied that at equilibrium, value of change in G,gibbs free energy and S, entropy should be zero. But...read the question-
The enthalpy of combustion of dihydrogen, cyclohexene and cyclohexaneare -241, -3800, and -3920 KJ mol​- respectively. The temperature at which the reaction is at equillibrium is
  1. 285.7 K
  2. 273 K
  3. 450 K
  4. 300 K
Here both G and S should not change. So automatically, T^S would become zero as entropy should be zero if the reaction is in equillibrium. (^ means del i.e. change)

Subject: Chemistry, asked on 22/5/15

Given that bond energies of H--Hand Cl--Cl bonds is 430 KJ mol​- and 240 KJ mol- respectively. Enthalpy of formation of HCl is -90 KJ mol-. Bond enthalpy of HCl is
  1. 290
  2. 425
  3. 380
  4. 245

Here in the question the answer according to the book is (c) i.e. 380 KJ mol-. But if we calculate the question for 1 mole of HCl then the answer is coming (b) . I want to ask that while calculating enthalpy, what stoichiometry should we use for the reactants?

Subject: Chemistry, asked on 16/5/15

Sir/Mam, thereare many questions given in study material which are not answered completely,sometimes the formulae are not given and sometime the calculation is incomplete! please correct them as soon as possible!

Subject: Chemistry, asked on 1/5/15

Is Heat of Combustion always taken as negative ?

Subject: Chemistry, asked on 21/4/15

The percentage s-characterin the hybrid orbitals in methane,ethene and ethyne are respectively a)25,50,75 b)25,33,50 c)10,20,40 d)50,75,100

Subject: Chemistry, asked on 14/4/15

8 gm of oxygen at 300 K is compressed to half of the volume under isothermal and reversible condition. Work done on the system (in cal) is?

Subject: Chemistry, asked on 12/4/15

The standard molar heat of formation of ethane, CO2 and water (l) are respectively -21.1,-94.1 and -63.3 kcal. The standard molar heat ofcombustion of ethane will be ?

Subject: Chemistry, asked on 11/4/15

The equilibrium constant for certain reaction is 100.If the value R is given to be 2 cal/k/mole ,then standard gibbs free energy change will be ?

Subject: Chemistry, asked on 5/4/15

an athlete takes 100 gm of glucose of energy equivalent to 1560 kJ. how much amount of energy is uptakenby 1 gm molecule of glucose ?

Subject: Chemistry, asked on 5/4/15

what is the work done correponding to 200 cal of heat

Subject: Chemistry, asked on 5/4/15

When 1 mole of monoatomicideal gas at T K undergoes adiabatic change under a constant external pressure of 1 atm, changes volume from 1L to 2L. Then, the final temperature in Kelvin would be ?

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