o make a long story short, my youngest daughter decided to endure 
through 4 semesters of chemistry, and now is paying up for it. She is 
a talented little girl, but science is not her thing and it hurts for 
me to see her study so hard but understand so little. It runs in the 
family. I wanted to help myself, but me and my wife are no scientists 
at all, plus it was so long ago. Tutoring is very very weak at where 
she goes, and we know few friends around here who are capable of 
helping, most of which already are looking at us the wrong way for 
asking so much. I decided to open my pocket and let you, Chemistry 
folks, help us out. I secretly took the next set of questions from my 
daughters assignment section, and here they are. I understand that 
many (or most) of you would have the problem to giving direct help 
like this, "learning and understanding the material is the most 
important", right ? Wrong. Only but a few of you would understand the 
pain I feel when I see my daughter quietly cry in her room over her 
low assignment grades after hours and hours of studying daily. 
  
Below I copied down some of the questions and choice answers that came
along. I tried my best to copy down everything number to number, word 
for word. Its a little bit difficult to transfer everything to text, 
but I tried. Please feel free to clarify if you did not understand a 
part. 
  
I am asking for a list of answers to the problems, in numerical + 
content format, as such : 
  
Question 1: Answer 3. The number of moles is 4.0.  
Question 2: Answer 5. The reaction is reversed.  
  
Time is an issue, but I would like the answers to be correct. I do not
want to check my daughters answers and tell her that one of her 
correct answers is incorrect simply because what was given to me is a 
wrong answer. Once again I apologize for such rude question, but I am 
desperate, and I ran out of all other options. I am also considering a
big tip for those who'll work hard on these, do all (or most) of the 
questions, provide the correct answers and hopefully as soon as 
possible. 
  
Thank you once more. You are my last hope.  
 
I'm breaking a list questions into separated entries as bobbie7-ga
suggested
 
(Thank you bobbie7-ga). Please provide the answer to the following
problems:

1) Given the equilibrium reaction

	MgSO4(s) <--> MgO(s) + SO3(g)

which of the following statements is true ?

1. The same equilibrium condition would result if we started with only pure 

MgSo4(s) in a closed container as if we started with only pure MgO(s) in a 

closed container.

2. Decreasing the volume of the closed container at constant temperature 

would result in more MgO(s) being formed.

3. At equilibrium, the forward and reverse reactions have stopped.

4. If the container were opened to the atmosphere, eventually only MgSO4(s) 

would remain.

5. If pure MgSO4(s) were placed in a closed container filled with N2(g) at 

1atm, the total pressure would increase, due to SO3(g) being formed.
 


2) Consider the reaction:

	N2 + 3H2 <--> 2NH3

Increasing the volume of the reactor without removing or adding any 

reactants or products will

1. (Z3) increase the value of the equilibrium constant.

2. (Z2) decrease the value of the equilibrium constant.

3. (Z4) will change the pressure in the reactor.

4. Both (Z1) and (Z4)

5. (Z1) not affect the equilibrium constant.

Hello -

1) Given the equilibrium reaction 
 
 MgSO4(s) <--> MgO(s) + SO3(g)


   1 - this is untrue, if only pure MgO was in a closed container,
there would
       be no S03 with which to react to form MgSO4, so, this reaction
would not
       take place.  If pure MgSO4 was in a container, the reaction
would still
       proceed
   2 - decreasing the volume of the container would increase the
relative
       concentration of the reactants, thereby driving the reaction
towards the
       products, producing less MgO not more
   3 - at equilibrium, the reactions have not stopped, their rates are
simply
       equal such that there is no net change in the amount of product
or
       reactant, so, untrue
   4 - untrue - if the container were open to the atmosphere, SO3
would escape,
       therefore the concentration of SO3 would be constantly
diminishing, this
       would drive the reaction towards more consumption of products,
so, less
       MgSO4
   5 - in this case, the pressure would increase as SO3 is formed - N2
is not
       a reactant in this case and thus it's pressure does not
directly
       influence the reaction

so, answer - 5 - If pure MgSO4(s) were placed in a closed container
filled with N2(g) at 1atm, the total pressure would increase, due to
SO3(g) being formed

2)  increasing the volume of the reactor, without changing the amount
of reactants will not change the equilibrium constant - hence it's
name "constant".  Increasing the volume will however, decrease the
pressure of the vessel - pressure is related to the number of
molecules divided by the volume, so, if the volume goes up, and the
number of molecules stays the same, the pressure will decrease.  So,
this gives us to true answers, Z1 and Z4.

answer - 4 Both (Z1) and (Z4) - not affect the equilibrium constant
and will change the pressure in the reactor

Please feel free to ask for any clarification needed.

synarchy


reference:
1) - http://hsc.csu.edu.au/chemistry/core/acidic/chem935/chem935net.html
see section on "explain the need for refluxing" for a similar
situation

2) http://www.hyper-ad.com/tutoring/chemistry/chem_eqm.htm

search
equilibrium chemistry

Thank you, great help. Keep up the good work!