The molar mass of h2o is 18.01 g/mom . the molar mass of o2 is 32.00 g/moo .what mass of h2o on grams must react to produce 50.00 g of o2

Oxygen can be obtained from water using electrolysis process as follows:
2 H2O > 2H2 + O2

It is given that: 
molar mass of water = 10.01 grams and molar mass of O2 = 32 grams

From the balanced chemical equation, we can conclude that:
2 moles of water produce 1 mole of oxygen
2 x 18.01 = 36.02 grams of water produce 32 grams of oxygen.

To calculate how many grams of water must react to produce 50 grams of oxygen, we can use cross multiplication as follows:
mass of required water = 56.28125 grams

Yes it would be a physical change.

Idk the answer sorry