[Antonio8]

YBa2Cu3O(7−x)(s) + ([ 7/2]−x)H2(g) → [ 1/2]Y2O3(s) + 2BaO(s) +3Cu(s) + ([ 7/2]−x)H2O(g)
35.937 ± 0.005 mg of solid YBa2Cu3O(7−x) reacts completely, according to the above equation, in a stream of hydrogen gas at 1000°C, leaving 33.242 ± 0.005 mg of solid residue.

(For the purpose of this exercise treat the values below as if they were exact.)

Molar mass of YBa2Cu3O(7−x) is (666.194 - 15.9994x)
Mass equivalent of (0.5Y2O3 + 2BaO + 3Cu) is 610.196

Calculate the value and (absolute) uncertainty of x.


I know how to do gravimetric analysis, but I don't get this. Any help would be great.