Calculate the weight proportion of H2O in Na2S2O2.5H2O?

1 Answer
Oct 21, 2017

Are you sure you don't mean #"sodium thiosulfate pentahydrate"#, i.e. #Na_2S_2O_3#? I make #"percentage water"# approx. #60%#.

Explanation:

We can calculate the percentage of water BY mass in #Na_2S_2O_3*5H_2O#....

i.e. #="Mass of water"/"Mass of hydrate"=(5xx18.01*g*mol^-1)/(158.11 *g*mol^-1)xx100%#

#=??%#

Just in regard to #S_2O_3^(2-)#, I have always liked to imagine this as #SO_4^(2-)# where ONE of the oxides has been replaced by sulfide ion, the which assumes the SAME oxidation number as oxide, and thus we gots #S(VI+)# and #S(-II)#, an AVERAGE oxidation state of #S(+II)#.