Question

20.40 g of solid Na2S2O3 is added to enough water to make 500 mL of solution. A 10 mL sample of that solution is diluted to a final vol. of 250 mL. What is the concentration of sodium ions in the resulting solution?

Answer 1

first find how many \(Na^+\) there are in that mass. Figure out the stock concentration, then use the dilution formula, \(M_1V_1=M_2V_2\), to find the new \([Na^+]\).