Asked by Chem is try
8.3 grams of NaCl and 3 grams of KBr were dissolved in 47 mL of water. What is the mole fraction of KBr in the solution?
I know that the mole fraction of the KBr and Nacl (without using the mL H2O is .2, but, i am confused on where i use that mL in the problem.) Please help!
I know that the mole fraction of the KBr and Nacl (without using the mL H2O is .2, but, i am confused on where i use that mL in the problem.) Please help!
Answers
Answered by
bobpursley
The wording is a bit ambiguous, to me.
Normally, one would want the mole fraction of the <u> solutes</u>, which would be
fraction=molesKBr/(molesKBr+molesNaCl)
However, the wording is not as specific as this. As it is worded, one has to inclue the moles of water, so
fraction=MolesKBr/(moleswater+molesNaCl+molesKBr)
How do you get moles of water?
moleswater=densitywater * volumewater/molmass water
Normally, one would want the mole fraction of the <u> solutes</u>, which would be
fraction=molesKBr/(molesKBr+molesNaCl)
However, the wording is not as specific as this. As it is worded, one has to inclue the moles of water, so
fraction=MolesKBr/(moleswater+molesNaCl+molesKBr)
How do you get moles of water?
moleswater=densitywater * volumewater/molmass water
Answered by
Chem is try
i got 1.2 but i don't think i did it right. below is my work:
3g(1mole/199g)=.03moles KBr
.03/(1moleH2O+.03molesKBr+.14moles NaCl)= 1.2
moles H2O = (1(47))/47=1
3g(1mole/199g)=.03moles KBr
.03/(1moleH2O+.03molesKBr+.14moles NaCl)= 1.2
moles H2O = (1(47))/47=1
Answered by
Chem is try
nevermind,i got .02...did i do this correctly??
Answered by
bobpursley
Your math is right, however, in the 3 grams (one significant figure), I suspect the writer was sloppy, and meant at least 3.00 grams
3.00/199=.00151moles. I don't know how you got .03 out of that.
How did you get moles water as 1?
3.00/199=.00151moles. I don't know how you got .03 out of that.
How did you get moles water as 1?
Answered by
Chem is try
d=m/v=47g/47mL
because 1g water = 1mL water
moles= dv/m=1(47)/47=1
because 1g water = 1mL water
moles= dv/m=1(47)/47=1
Answered by
bobpursley
Nuts to that.
Moles water= masswater/molmasswater=47g/18g/mol= not 1
Moles water= masswater/molmasswater=47g/18g/mol= not 1
Answered by
Chem is try
so, i got 6.82 moles of water and plug that in and get .00361, right?
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.