Question

Calculate for the molarity of 1.0L sodium chloride solution containing 250.0 grams NaCl (FW=58.44g/mol)?

Answer 1

Molarity is expressed through the equation,

`"molarity"="moles of solute"/"liters of solution"`

So here, we must convert `250 \ "g" \ NaCl` into moles.

`NaCl` has a molar mass of `58.44 \ "g/mol"`. And so, we got here:

`(250color(red)cancelcolor(black)"g")/(58.44color(red)cancelcolor(black)"g""/mol")~~4.28 \ "mol"`

We also have here `1 \ "L"` of solution, and the molarity will be:

`"molarity"=(4.28 \ "mol")/(1 \ "L")=4.28 \ "mol/L"`

`=4.28 \ "M"`