Question

Salt (NaCl) placed on an icy sidewalk causes ice to melt. Melting is a result of freezing-point depression. The salt dissolved in water that makes up ice and forms a solution that has a lower freezing point then pure water. If 500 g of salt is added to 4.00 kg of water, what is the molality? SHOW YOUR WORK.

Answer 1

To calculate the molality, we need to know the moles of salt and the mass of the solvent (water) in kilograms.First, let's convert the mass of salt to moles. We can do this using the molar mass of NaCl, which is 58.44 g/mol:moles of NaCl = mass of NaCl / molar mass of NaCl

moles of NaCl = 500 g / 58.44 g/mol

moles of NaCl = 8.55 molNext, let's convert the mass of the solvent to kilograms:mass of solvent = 4.00 kgNow we can calculate the molality:molality = moles of solute / mass of solvent in kg

molality = 8.55 mol / 4.00 kg

molality = 2.14 mol/kgTherefore, the molality of the salt solution is 2.14 mol/kg.

Step-by-step explanation:

Answer 2

To calculate the molality, we need to know the moles of salt and the mass of the solvent (water) in kilograms.First, let's convert the mass of salt to moles. We can do this using the molar mass of NaCl, which is 58.44 g/mol:moles of NaCl = mass of NaCl / molar mass of NaCl

moles of NaCl = 500 g / 58.44 g/mol

moles of NaCl = 8.55 molNext, let's convert the mass of the solvent to kilograms:mass of solvent = 4.00 kgNow we can calculate the molality:molality = moles of solute / mass of solvent in kg

molality = 8.55 mol / 4.00 kg

molality = 2.14 mol/kgTherefore, the molality of the salt solution is 2.14 mol/kg.