a solution is made by dissolving 25 g NaCl in enough water to make 1.0 L solution. Assume that density of the solution is 1.0 g/mL. calculate the mass percent, molarity, molality, and mole fraction of NaCl.

Question

a solution is made by dissolving 25 g NaCl in enough water to make 1.0 L solution. Assume that density of the solution is 1.0 g/mL. calculate the mass percent, molarity, molality, and mole fraction of NaCl.

Answer 1

I responded below. mass percent is not right (should be 2.5%) but M and m are right.

Answer 2

To calculate the mass percent, molarity, molality, and mole fraction of NaCl in the solution, we need to use the formula:

Mass percent = (mass of solute / mass of solution) x 100
Molarity (M) = (moles of solute / volume of solution in liters)
Molality (m) = (moles of solute / mass of solvent in kilograms)
Mole fraction = (moles of NaCl / total moles of solute and solvent)

First, let's calculate the moles of NaCl in the solution:
Molar mass of NaCl = 22.99 g/mol (atomic mass of Na) + 35.45 g/mol (atomic mass of Cl) = 58.44 g/mol
moles of NaCl = mass of NaCl / molar mass of NaCl
= 25 g / 58.44 g/mol
≈ 0.4282 mol

Next, let's calculate the mass of the solution:
density = mass of solution / volume of solution
mass of solution = density x volume of solution
= 1.0 g/mL x 1000 mL
= 1000 g

Now, we can calculate the mass percent:
mass percent = (mass of NaCl / mass of solution) x 100
= (25 g / 1000 g) x 100
= 2.5%

Next, let's calculate the molarity:
molarity (M) = (moles of NaCl / volume of solution in liters)
= (0.4282 mol / 1.0 L)
= 0.4282 M

Now, let's calculate the molality:
molality (m) = (moles of NaCl / mass of solvent in kilograms)
= (0.4282 mol / 1.0 kg)
= 0.4282 m

Finally, let's calculate the mole fraction:
We need to know the number of moles of water in the solution. Since water is the solvent, we assume that the mass of the solution is equal to the mass of the water.

moles of water = mass of water / molar mass of water
= mass of solution / molar mass of water
= 1000 g / 18.015 g/mol
≈ 55.5 mol

mole fraction of NaCl = moles of NaCl / (moles of NaCl + moles of water)
= 0.4282 mol / (0.4282 mol + 55.5 mol)
≈ 0.0077

Therefore, the mass percent of NaCl in the solution is 2.5%, the molarity is 0.4282 M, the molality is 0.4282 m, and the mole fraction of NaCl is 0.0077.

Answer 3

Don't be coy. How much do you know how to do and exactly what do you not understand? I'm not working these so you can check your answer but I will be glad to help you through what you don't understand.