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450 moles of NaCl are dissolved in 95.0 mL of water. Calculate the molarity of the NaCl solution.
a.0.0047 MB)0.21 MC)2.1 MD)4.7 M

Respuesta :

JonHenderson55
The answer is:  [D]:  "4.7 * 10³ M "
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Note:
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Molarity, "M", equals "moles of solutes per Liters solvent" ; or "mol / L ".

Given: "450 mol / 95.0 mL" ; convert to:  "mol/L" ("moles per unit Liter (L)" ) ;

Note: The exact measurement:  1000 mL = 1 L .

(450 mol / 95.0 mL) *(1000 mL / 1 L) = (450 * 1000) / (95.0) = 450000 / 95.0 =

         450000 mol / 95 L  ;  (note only "TWO (2) significant figures in 4
                                  "450000" ; so we can rewrite "95.0" as "95"                                                                         (only "2" significant figures).
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 = (450000/95) mol / L =  4736.8421052631578947    ;
                                        → round to "2" significant figures ; 

                                        →   =   4.7 * 10³ moles / L  ;

                                        →   =   4.7 * 10³ M .
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