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What would you need to do to calculate the molality of 0.2 kg of NaCl in 3 kg of water?

Respuesta :

ccrissinger
convert the .2 kg of NaCl to moles of NaCl. hope this helps
aabdulsamir

Answer:

1.14mol/kg

Explanation:

Mass of solute = 0.2kg

Mass of solvent = 3kg

Molality = no. Of moles / kg of solvent.

0.2 kg of NaCl = x moles

No. Of moles = mass / molarmass.

Molar mass of Na = 23

Molar mass of Cl = 35.5

Molar mass of NaCl = 23 + 35.5 = 58.5g/mol

0.2kg = 0.2 × 1000g = 200g.

No. Of moles = 200 / 58.5

No. Of moles = 3.419moles.

Molality = no. Of moles / kg of solvent.

Molality = 3.419 / 3.0

Molality = 1.139 mol/kg = 1.14mol / kg