# Chem lab last question!! Urgent help

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Commodity prices of NaCl and urea are about \$0.033/lb for NaCl (as rock salt) and about \$0.10/lb for urea. Calculate the cost of treating 1000 lb of ice on a surface to produce a solution that melts at -3.9 degrees Celsius with each chemical. I know you use to delta T= mkfi but after i find m idk what to do next please help

• Chem lab last question!! Urgent help -

delta T = i*Kf*molality
Plug in 3.9 for delta T, i = 2 for NaCl (i - 1 for urea), Kf, and solve for molality.

molality = mols/kg solvent.
You have m and kg solvent(convert 1000 lb to kg) and solve for mols.

mol = grams/molar mass. You have mols and molar mass; solve for grams.

I would convert cost/lb to cost/gram, and grams urea x cost/g = total cost.
grams NaCl x cost/g = total cost.

• Chem lab last question!! Urgent help -

THANK YOU SO MUCH!!!

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Commodity prices of NaCl and urea are about \$0.033/lb for NaCl (as rock salt) and about \$0.10/lb for urea. Calculate the cost of treating 1000 lb of ice on a surface to produce a solution that melts at -3.9 degrees Celsius with each …