[MaeP]

Im working on showing (through stoichiometry) how much Oxygen and Glucose would be theoretically formed if 1L (1000g) of water was consumed by a plant (through photosynthesis).

The formula for photosynthesis is:
6H₂O + 6CO₂ ---> C₆H₁₂O₆ + 6O₂
   6     :    6     :        1        :   6        <--- the ratio's

m(H₂O) = 1000g
M(H₂O) = 18
therefore: n(H₂O) = 1000/18 = 55.56mol

ratio of H₂O to CO₂ = 1:1 so n(CO₂) = 55.56mol

ratio of H₂O to O₂ also 1:1 so n(O₂) = 55.56mol
m = nM
M(O₂) = 32
m(O₂) = 55.56 x 32 = 1777.78g
Density of oxygen = 1.429g/L therefore in Litres the amount of oxygen produced would be 1244.07?

ratio of H₂O to C₆H₁₂O₆ is 6:1 therefore n(C₆H₁₂O₆)=9.26,
M(C₆H₁₂O₆) = 180.16,
m=nM, m(C₆H₁₂O₆) = 1668.27g?

Is this correct? It doesnt seem very plausible (1 litre of water will give 1244 litres of oxygen??)

[Borek]

Is this correct? It doesnt seem very plausible (1 litre of water will give 1244 litres of oxygen??)

Insert 55.56 moles into pV=nRT and you will have correct answer much earlier, without the need for oxygen density.

Your result is correct. It may seem large, but take a look at the density of oxygen - it is very low. Well, it's a gas after all

[MaeP]

I forgot about the general gas equation (should have used that to check my answer ), but I did have to use stoichiometry in this case (that was the task)  .
Thanks for the help