Question

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

Answer 1

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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