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.
help please
25g/58.44g NaCl=.428 mol
1000 grams of solvent H20
25g/58,44 g x100= 42.8 % mass percent
molarity .428 mol/1.0 L= .428 M
molality= .428 mol/1 Kg= .428 molal is that right?
help please
answered below.
may i ask where did the 1.0 g/mL go?
I want to do my assignment
Let's calculate the mass percent, molarity, molality, and mole fraction of NaCl step by step.
1. Mass Percent:
Mass percent is calculated by dividing the mass of solute (NaCl) by the mass of the solution (NaCl + water) and multiplying by 100.
Mass of NaCl = 25 g
Total mass of solution = 25 g + 1000 g = 1025 g
Mass percent = (25 g / 1025 g) x 100 = 2.44%
Therefore, the mass percent of NaCl in the solution is 2.44%.
2. Molarity:
Molarity is calculated by dividing the number of moles of solute by the volume of the solution in liters.
Number of moles of NaCl = 25 g / 58.44 g/mol = 0.428 mol
Volume of solution = 1.0 L
Molarity (M) = 0.428 mol / 1.0 L = 0.428 M
Therefore, the molarity of NaCl in the solution is 0.428 M.
3. Molality:
Molality is calculated by dividing the number of moles of solute by the mass of solvent in kilograms.
Number of moles of NaCl = 0.428 mol
Mass of water = 1000 g
Mass of water in kg = 1000 g / 1000 = 1 kg
Molality = 0.428 mol / 1 kg = 0.428 molal
Therefore, the molality of NaCl in the solution is 0.428 molal.
4. Mole Fraction:
Mole fraction is the ratio of the moles of one component (NaCl) to the total moles of all components in the solution.
Mole fraction of NaCl = Number of moles of NaCl / Total moles of all components
Number of moles of NaCl = 0.428 mol
Number of moles of water = Mass of water / Molar mass of water
Mass of water = 1000 g
Molar mass of water = 18.015 g/mol
Number of moles of water = 1000 g / 18.015 g/mol ≈ 55.49 mol
Total moles of all components = 0.428 mol + 55.49 mol = 55.918 mol
Mole fraction of NaCl = 0.428 mol / 55.918 mol ≈ 0.00765
Therefore, the mole fraction of NaCl in the solution is approximately 0.00765.
So, the calculations for the mass percent, molarity, molality, and mole fraction of NaCl in the solution are as follows:
- Mass percent = 2.44%
- Molarity = 0.428 M
- Molality = 0.428 molal
- Mole fraction ≈ 0.00765