[ARGOS++]

Dear BAMxTiFFANY;

Nearly correct!, - but you forgot the units!

Now we know that 1.050 kg solution contains 73.05 g sodium chloride.
     a.)    How much grams are left for water?
     b.)    And what’s then the molality?

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

Nearly correct!, - but you forgot the units!

Now we know that 1.050 kg solution contains 73.05 g sodium chloride.
     a.)    How much grams are left for water?
     b.)    And what’s then the molality?

Good Luck!
                    ARGOS⁺⁺

um 976.95g h20 O_o
73.05 over 976.95 which is.. .07477mole/kg?


now i have to show how i did it on paper O_o
how do i do that?

[ARGOS++]

Dear BAMxTiFFANY;

The weight of water is correct!

But then you are toooo fast and that’s why it is not correct:  73.05g are not 0.07305 moles!

!!!!!! Please calculate all times with units  !!!!!!!

So remember: 73.05g are 1.25 moles sodium chloride! So what’s now the result for b.)?

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

The weight of water is correct!

But then you are toooo fast and that’s why it is not correct:  73.05g are not 0.07305 moles!

!!!!!! Please calculate all times with units  !!!!!!!

So remember: 73.05g are 1.25 moles sodium chloride! So what’s now the result for b.)?

Good Luck!
                    ARGOS⁺⁺

molality > mole of solute over kg of solvent

m =  1.25 solute over .97695 = 1.28mole/kg

[ARGOS++]

Dear BAMxTiFFANY;

Bravo!,  - That’s exact!

And now:
     c.)  How many moles are this 976.95g water?
     d.)  What’s now the mole fraction?

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

Bravo!,  - That’s exact!

And now:
     c.)  How many moles are this 976.95g water?
     d.)  What’s now the mole fraction?

Good Luck!
                    ARGOS⁺⁺

c) 54.23
d) uh (1.25 over 55.48 ) x100 = 2.25%

[ARGOS++]

Dear BAMxTiFFANY;

C.) is correct!

For d.) remember its definition! – mole-fraction is unit-less! So you have not to multiply be 100!
Can you do d.) once again?

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

C.) is correct!

For d.) remember its definition! – mole-fraction is unit-less! So you have not to multiply be 100!
Can you do d.) once again?

Good Luck!
                    ARGOS⁺⁺

oh woops so.. .0225?

[ARGOS++]

Dear BAMxTiFFANY;

Exact!

Now can you finally calculate the % w/w of the solution?

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

Exact!

Now can you finally calculate the % w/w of the solution?

Good Luck!
                    ARGOS⁺⁺

2.25% :]

dude your my new bff O:
can you help me with numero tres?
i can't figure out how to find the total moles for water..
i assumed 1 kg of kno3 and i got 9.89 moles of KNO3

[ARGOS++]

Dear BAMxTiFFANY;

Sorry!,  % w/w has nothing to do with mole-fraction!
Please use the definition of % w/w!

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

Sorry!,  % w/w has nothing to do with mole-fraction!
Please use the definition of % w/w!

Good Luck!
                    ARGOS⁺⁺

um it said percent by mass of sodium
and mole fraction of water :|
so you kinda got it backwards.. i think O:
its i think.. 2.25% and .9775

[ARGOS++]

Dear BAMxTiFFANY;

That’s not correct!,  -  w/w = weight/weight has nothing to do with moles too.

Good Luck!
                    ARGOS⁺⁺

[BAMxTiFFANY]

Dear BAMxTiFFANY;

That’s not correct!,  -  w/w = weight/weight has nothing to do with moles too.

Good Luck!
                    ARGOS⁺⁺

O:
im confused again..

[ARGOS++]

Dear BAMxTiFFANY;

What is the definition of % w/w?

Good Luck!
                    ARGOS⁺⁺