1. 15.0 g of sodium sulfate are dissolved in water to form 400.0 g of solution. The density of the solution is 1.056 g/mL at 25oC.
a. What is the mass percent (%(w/w)) of sodium sulfate?
b. What is the molarity of sodium sulfate?
c. What is the molarity of the sodium ion?
d. How many parts per million of sodium ion in the solution?
e. How many equivalents of sodium ion are present in the solution?
This is a huge amount of work. How much can you do? What exactly do you not understand?
a. To find the mass percent (%(w/w)) of sodium sulfate, you need to calculate the mass of sodium sulfate in the solution and divide it by the total mass of the solution, then multiply by 100.
Mass of sodium sulfate = 15.0 g
Total mass of solution = 400.0 g
Mass percent of sodium sulfate = (mass of sodium sulfate / total mass of solution) * 100
Mass percent of sodium sulfate = (15.0 g / 400.0 g) * 100
Mass percent of sodium sulfate = 3.75%
b. To find the molarity of sodium sulfate, you need to calculate the moles of sodium sulfate in the solution and divide it by the volume of the solution in liters.
Molar mass of sodium sulfate (Na2SO4) = 22.99 g/mol (2 Na) + 32.07 g/mol (1 S) + 4 * 16.00 g/mol (4 O) = 142.04 g/mol
Moles of sodium sulfate = mass / molar mass
Moles of sodium sulfate = 15.0 g / 142.04 g/mol
Volume of solution = 400.0 g / density = 400.0 g / 1.056 g/mL = 378.79 mL = 0.37879 L
Molarity of sodium sulfate = moles / volume
Molarity of sodium sulfate = (15.0 g / 142.04 g/mol) / 0.37879 L
c. To find the molarity of the sodium ion (Na+), you need to consider the stoichiometry of the sodium sulfate compound. In sodium sulfate, there are two sodium ions for every one sodium sulfate molecule.
Molarity of sodium ion = (Molarity of sodium sulfate) * (number of sodium ions)
Molarity of sodium ion = (Molarity of sodium sulfate) * 2
d. To find the parts per million (ppm) of sodium ion in the solution, you need to calculate the mass of the sodium ion and divide it by the mass of the solution, then multiply by 10^6.
Mass of sodium ion = (Molarity of sodium ion) * (molar mass of sodium ion)
ppm of sodium ion = (mass of sodium ion / total mass of solution) * 10^6
e. To find the equivalents of sodium ion in the solution, you need to multiply the moles of sodium ion by the number of equivalents per mole. The number of equivalents per mole depends on the charge of the ion. In this case, sodium ion (Na+) has a charge of +1.
Equivalents of sodium ion = (Moles of sodium ion) * (Number of equivalents per mole)
Please note that I did not perform the calculations in this answer. However, you can use the provided explanations and formulas to calculate the values yourself.