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Chemical Equilibrium

Distillation to determine difference in boiling points

Mixtures of propan-2-ol and propanone can be spearated by distllation due to their different boiling points. Explain why these compounds have such different boiling points even though they have very similar molar masses.





Boiling point(°C)



Molar mass(g/mol)




calculating mole fractions in Raoult's law problems

when we deal with the raoult's law equation for an ideal solution of 2 ideal liquids, do we have to use the number of moles at equilibrium to calculate the mole fraction of solvent in the solution? or can we use the initial number of moles ?

Determine the value of the equilibrium constant

1.    Determine the value of the equilibrium constant for the following three reactions, using the given equilibrium concentrations.  Remember [X] implies a concentration in moles per liter.

A  +  B  D C

[A] = 2.0  [B] = 3.0  [C] = 4.0




D  +  2E  D F  +  3G

[D] = 1.5; [E] = 2.0; [F] = 1.8; [G] = 1.2




N2(g)  +  3H2(g)  D 2NH3(g)

[N2] = 0.45; [H2] = 0.14; [NH3] = 0.62

effect of concentration on preciptate

Does production of  a precipitate decrease concentration?

Production of ammonia by Haber process

I only need help with the last three dot points.

Acid Base Equilibirum - Finding concentrations BEFORE equilibrium

What are the equilibrium concentrations of [H3O+], [CN-] and [HCN] if the concentration of HCN before equilibrium is 1.0 M?  Also, what is the pH of the solution? (Ka = 6.3x10-10)  Write out the entire ICE table for full credit.
I have no idea how to approach the problem when you need to find the values BEFORE equilibrium! I'm only familiar with how to find the values at equilibrium. Please help!!!

A gas has a volume of 2.0 L....

A gas has a volume of 2.0 L, and a pressure of 2.0 atm. If the pressure is increased to 4.0 atm, what is the new volume of the gas? 

I really just don't know how to even set this problem up. Thats my problem. Dont know where to start. Help me please...

calculation of pH......

1 millimole of Aluminium Hydroxide is taken for an experiment. At a certain temperature solubility product of aluminium hydroxide is 5 X 10^(-33) M^4 and formation constant of tetrahydroxy aluminate is(III) =1X10^34.

1.       Calculate the minimum PH at which all the aluminium hydroxide goes into 1 liter solution as tetrahydroxy aluminate(III)

2.       Calculate the maximum hydroxide ion in the solution formed when all the aluminium hydroxide goes into one litre aqueous solution as Aluminium (3+) ions

Confused on Acids and Bases in equilibrium??

How do i know when to use Ka or Kb when trying to find pH? Also how do i tell the difference between and acid and a base when the equation is written.somthing like NH3+H2O-->OH-+NH+4 ?

Can you help with this? Been stuck on it for a while. Teacher said that there are equations that I'm not using.

Urea ((NH2)2CO) is a waste product produced when the liver metabolises protein.  Urea can be decomposed to CO2(g) and NH3(g) according to the equilibrium (assume that this is the only reaction which occurs):


(NH2)2CO(s)  +  H2O(l)  ⇌  2NH3(g)  +  CO2(g)        Kp = 0.0702


The following thermodynamic data, measured at 298 K, apply to the above equation.



ΔfGo/ kJ mol-1









R = 8.314 J mol-1 K-1


(i)             Calculate ΔrGo for the above reaction and hence calculate ΔfGo for NH3(g).


(ii)          A certain amount of damp (NH2)2CO(s) is placed in a 1.00 L closed vessel and equilibrium is allowed to be established at 298 K.  At equilibrium the concentration of NH3(g) was found to be 0.0210 mol L-1.  Calculate the value of the equilibrium constant Kc.


(iii)        By considering the above equilibrium decide, with reasons, what will happen if 0.010 mol of NH3(g) and 0.010 mol CO2(g) are introduced into an empty 1.00 L vessel at 298 K.


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