Question

help please...A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 550mL of a solution that has a concentration of Na+ ions of 0.500M ?.

Answer 1

The grams needed are 15

Step-by-step explanation:

With the Na3PO4 volume and the Na+ concentration you can calculate the moles of Na+ that are present in the solution.

M stands for molarity which means moles of Na3PO4 (in this case) per liter of solution.

0.55 L * 0.5 M --> 0.275 moles of Na+. But each mol of Na3PO4 has 3 moles of Na+ in it, so to calculate the moles of Na3PO4 needed you must divide the concentration of Na+ in three.

0.275/3 = 0.0917

Now we calculate the molar mass of Na3PO4 which is 164 g/mol and multiply that for the amount of moles.

0.0917 mol * 164 g/mol = 15 grams of Na3PO4