ECAT and MCAT Preparation: Post your doubts here!

[1357913579]

excellent... i think your answer is right. there might be a misprint in the book!
Thanks a lot

no prob bro,
your welcome

 

[smzimran]

Two water solutions are made in the laboratory, one of the glucose (molar mass = 180 grams) , the other of sucrose (molar mass = 342 grams) . If the glucose solution had 180 grams in 1000 grams of water and the sucrose had 342 grams in 1000 grams of water, which statement is most accurate about the freezing points of the solutions ?

(A) The glucose solution would have the lower freezing point.
(B) The sucrose solution would have the lower freezing point.
(C) The freezing point of the sucrose solution would be lowered twice as much as that of the glucose solution.
(D) Both solutions would have the same freezing point.
(E) The freezing point of the solutions would not be affected, because the solutes are both nonpolar.

The answer is D , explanation required, thanks!

 

[hassam]

see te moles are same........and freezing point depression is a colligative property...which will be different if no. of moles are different

 

[smzimran]

see te moles are same........and freezing point depression is a colligative property...which will be different if no. of moles are different

if moles were different, the number of moles is greater means freezing point is greater!

 

[Goodfella]

so how was the giki test guys? mine went umm ok, there's hope!

 

[smartangel]

hey..can someone please help me out.. for ziauddin university in karachi..do i need to prepare for mcat or they have their own syllabus?

 

[Mustehssun Iqbal]

so how was the giki test guys? mine went umm ok, there's hope!

good to know you have hope. most of the giki students i know returned with quite gloomy faces :\

 

[HIMYM forever!!]

so how was the giki test guys? mine went umm ok, there's hope!

Didn't even take the test I know only two people who took the test. One said he flunked and the other said it was pretty easy.

 

[Mustehssun Iqbal]

Ah it's really hard to explain maths like this. Anyway i'll try again.
Do you know how to expand a 3x3 determinant? This is the same thing. When you expand a 3x3 determinant, you are actually converting it into a lesser order matrix ,i.e a 2x2 matrix which is then solved by 'ad-bc' formula.
Now the given determinant was of 5x5 order. You expand it/convert it into a lower order determinant, i.e 4x4
You have got more than 1 4x4 determinants corresponding to the number of elements in that row or column. Now the technique was that if we use such a row or column for expansion which has only one non-zero entry, we get only 1 4x4 determinant. Had we considered a row or a column having more than 1 non zero entries, there would have been more than 1 4x4 determinants, which would have made the problem confusing.
Now using that 1 4x4 determinant, we again consider a row or a column for expansion which would give only one lesser order i.e, 3x3 determinant.
Then we expand the 3x3 determinant and solve it by ad-bc. I hope that helped

Assalamu alaikum,
I didn't understand your explanations but they sounded smart.
I solve determinants by the diagram method where you write the matrix and add up the diagonals from the right and subtract them from the sum of the diagonals from the left side... It works on 3 by 3 and 2 by 2 matrices. Is there any way to apply the same method on a 5 by 5 matrix?? If yes, please tell. thanks

 

[Mustehssun Iqbal]

smzimran ^ ??

 

[Mustehssun Iqbal]

it looks like there's no diagram way of solving 5 by 5 matrix. so is it necessary for me to learn the method of expanding a matrix??

 

[gogabaji]

solve this one

answer is definitelr a because water is a very bad heat conductor temperature of water at bottom is different from that at the top so ice berg melts at the base and not at the top

 

[Mustehssun Iqbal]

 

[Goodfella]

can anyone here explain me the difference b/w some brackets, i've met with many questions in which all the options are same except the brackets

[ ]
( )
which one to use, in different circumstances? fsc students will be able to answer this

 

[gogabaji]

yes

 

[Mustehssun Iqbal]

can anyone here explain me the difference b/w some brackets, i've met with many questions in which all the options are same except the brackets

[ ]
( )
which one to use, in different circumstances? fsc students will be able to answer this

not an Fs.c student but seeing the time shortage for the nust test, and assuming no Fs.c students present on xtremepaper forums :\ ...
( ) these brackets , when another pair of brackets come in them, they become [ ]
e.g. [ ( ) ]
and then another bracket comes in them they're like this;
{ [ ( ) ] }
i guess you know this already...
In sets { } represent a set...
and ( ) represent an ordered pair...
e.g. (2, 3) is an ordered pair... and
{ 2, 3 } is a set.
a set can contain an element just once.
an ordered pair can contain the same element more than once.
for example, (2, 3 , 3 ) can exist while;
{ 2, 3, 3 } does not exist!
and in ordered pair ( ) arrangement matters, unlike in sets{ }.
e.g. (2, 3 ) = (2, 3)
but (3, 2) is not equal to (2, 3)
also ;
{2, 3} = {3, 2};

 

[Goodfella]

not an Fs.c student but seeing the time shortage for the nust test, and assuming no Fs.c students present on xtremepaper forums :\ ...
( ) these brackets , when another pair of brackets come in them, they become [ ]
e.g. [ ( ) ]
and then another bracket comes in them they're like this;
{ [ ( ) ] }
i guess you know this already...
In sets { } represent a set...
and ( ) represent an ordered pair...
e.g. (2, 3) is an ordered pair... and
{ 2, 3 } is a set.
a set can contain an element just once.
an ordered pair can contain the same element more than once.
for example, (2, 3 , 3 ) can exist while;
{ 2, 3, 3 } does not exist!
and in ordered pair ( ) arrangement matters, unlike in sets{ }.
e.g. (2, 3 ) = (2, 3)
but (3, 2) is not equal to (2, 3)
also ;
{2, 3} = {3, 2};

Thanks a lot, but i know this already, but there is a thing in fsc syllabus which i can't understand, even in the e-cat books a question comes in which all four options are the same only the brackets are changed e.g

(2,3)
[2,3]
(2,3]
[2,3)

and HIMYM Forever is an fsc student!

 

[HIMYM forever!!]

Thanks a lot, but i know this already, but there is a thing in fsc syllabus which i can't understand, even in the e-cat books a question comes in which all four options are the same only the brackets are changed e.g

(2,3)
[2,3]
(2,3]
[2,3)

and HIMYM Forever is an fsc student!

Lol i'm an fsc student. I guess i could help you =P well [ ] simply means closed interval. E.g [2, 4] means the number line from 2 to 4 INCLUDING 2 and 4. ( ) is an open interval which means the boundary values are not included. E.g, (2, 4) means the number line between 2 and 4 excluding 2 and 4. (] and [) are semi open- semi closed intervals.

 

[saqib shaikh]

PIEAS UNIVERSITY MCQ'S 2012:-

1)would the guests like the dinner? the cooks _____ hard to make it delicious. anyone remembers the answer to this mcq??
A. HAD WORKED
b. Will work

2) What is the angle between NH^3 Molecule? I clicked on 109 Degree

 

[saqib shaikh]

IS THERE ANY QUOTA SYSTEM IN PIEAS UNIVERSITY???