Tough as Physical chemistry

[sachinkhanal]

These days among many subject i am having a bit problem in Physical chemistry . I am not being able to solve the physical and numerical problems of chemistry , Is there any senior member making me little clear about using Molecular functions formula in a particular way ?? Help me seniors

 

[destined007]

which topic of physical chemistry?

 

[OakMoon!]

There are different techniques to solve the numerical questions in different chapters of physical chemistry that you'll need to get accustomed to. Just get to know these techniques from the worked examples in the black book and try to solve questions from the past papers using marking schemes. A time will come when you have mastered these topics.

 

[sachinkhanal]

i am not getting mol concept , i know all the formulas but not sure to use them at all .. Please make me clear about the concerntration and molar volume , relative molar mass and soo on , can you suggest and example to make me clear about those stuffs ? Please do it .. i have an internal exam on 15th of sept. so hurry bros

 

[OakMoon!]

For that you'll need to practice alot of questions. If you don't get a specific question than you should post the question here. You'll understand once we solve the question for you.

 

[sachinkhanal]

Percentage yeild .
1.From 23g of ethanol are obtained 36 g of ethyl ethanoate by estericication with ethanoic acid in the presence of concentrated sulphuric acid. What percentage yeild of the reaction ?


Explain me how to do bro , iim totally weak to these problems .. I am totaly confuse in relative atomic mass , molar mass etc .. can you explain that to me bro with examples ?

 

[mrpaudel]

U should know what percentage yeild means...!! for any reaction, u expect to form a certain amount of product theoritically but the amount formed is less than we expected if we perform that experiment..!! thus....Suppose...for eg..as u have said...
Ethanol+Ethanoic acid-------->Ethyl Ethanoate+water....
1mole(46g) 1mole(88g)
bt...23g of ethanol is used...so

23g(0.5mol) should give 0.5mole(44g) of ethyl ethanoate..........
Now...the amount that should be given is 44g of ethyl ethanoate bt the only 36g of ethyl ethanoate is found....
Thus, Percentage yeild=(experimental mass/theoritical mass)* 100 = 36/44 * 100= 81.8%