concentration calculation problem

[Smooth Operater]

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upon evaporating at 25 ml sample of a table salt, NaCl, solution to dryness, 0.585 g of salt were obtained. the concentration of the solution, at the start, was:

how would you calculate this problem? thanks!

 

[joonkimdds]

upon evaporating at 25 ml sample of a table salt, NaCl, solution to dryness, 0.585 g of salt were obtained. the concentration of the solution, at the start, was:

how would you calculate this problem? thanks!

let me guess...
we get molar mass of NaCl and get the difference with 0.585g to find out how much is gone then using the ratio get the original volume other than 25ml. using those two new numbers we found substitute it into
concentration= molarity = g/volume at the start.

am i wrong? i think i m wrong 😀

 

[Manyak222]

upon evaporating at 25 ml sample of a table salt, NaCl, solution to dryness, 0.585 g of salt were obtained. the concentration of the solution, at the start, was:

how would you calculate this problem? thanks!

.585g/.585+25g

since 25 ml of h2o is 25g of h2o.

 

[Smooth Operater]

the correct answer is 0.585g/58.5 g/mole * 0.025L . But I am not sure how you would get it lo?

 

[doc toothache]

You have .585 g of salt in 25 ml of solution. For 1 liter you would have

25:.585=(1000):xg solving for x
x=40 (.585) g/L

1 molar would be 58.5g, then

1m:58.5=?M: (40)(.585)
solving for m= (40)(.585):58.5
M=.4

 

[Smooth Operater]

mmm, ur answer is still wrong.

does 0.585 g = 0.585 ml?

 

[doc toothache]

What is the correct answer?
for salt, 0.585g is not equal to 0.585ml

 

[MasonPrehealth]

what type of concentration are you being asked about? Molality, molarity, or molar-percentage, or weight-percentage?

 

[Smooth Operater]

molarity

 

[doc toothache]

It is a 0.4 Molar solution (moles/liter), and
25ml (0.025L) contains .585g/58.50g/moles. The answer is in moles present in 25 ml not the molarity of the solution.

 

[deleted100801]

clearly the answer is 42