Mass number = protons + neutrons = 34+46 =80
the element with an atomic number of 34 and mass number of 80 is selenium
Mass of sodium thiosulfate
is 110. g
Volume of the solution is 350. mL
Calculating the moles of sodium thiosulfate:
= 0.696 mol
Converting the volume of solution to L:

Finding out the concentration of solution in molarity:
