1. The problem statement, all variables and given/known data I had an inorganic lab this week which involved making VO(acac)2 from VOSO4⋅xH2O. In order to calculate the percentage yield, I need to work out x, that is, the number of water molecules coordinated with the vanadyl sulfate n-hydrate before the reaction. I'm stuck, because I know we didn't get a very high yield as we only had a short time to crystallise, and the yield we did measure wasn't very accurate as we had little time to dry the product before weighing (from mixing reagents to weighing product: less than an hour). As far as I know, without knowing how many water molecules there were in the vanadyl reagent, I can't know which was the limiting reagent & therefore what the percentage yield is, but if the mass of product we got is not close to what it should be stoichiometrically, I can't calculate x. Am I correct? Is there anything I can do? Detailed info below. [By the by: while I do need to work this out for a lab report, I'm posting here because I'd really appreciate some insight into the problem - I know the demonstrator bent the rules & told some classmates what x is & I can just ask them, but I'd like to see if there's a way to work it out. Everyone else has been carrying out this experiment in the same timeframe which implies that there might be a way to reason it out, even with imperfect data. Thanks in advance!] 2. Relevant equations Chemical equation: VOSO4⋅xH2O + Na2CO3 + 2C5H8O2 → VO(C5H7O2)2 + Na2SO4 + (x+1)H2O + CO2 3. The attempt at a solution Amounts of reagents used: Molar mass of Na2CO3 = 105.99 g mol-1 2.5 g used = (2.5 / 105.99) mol = 0.0236 mol used Molar mass C5H8O2 = 100.12 g mol-1 2.5 cm3 used Density of liquid C5H8O2 = (970 g / 1000 cm3) = 0.970 g cm-3 ⇒ 2.5 cm3 = (2.5 x 0.97) g = 2.425 g 2.425 g used = (2.425 / 100.12) mol = 0.0242 mol used Molar mass VOSO4⋅xH2O = [163.00 + 18.015x] g mol-1 2.5 g used If x = 1: 2.5 g = (2.5 / 181.015) mol = 0.138 mol theoretical yield If x = 2: 2.5 g = (2.5 / 199.03) mol = 0.126 mol theoretical yield If x = 3: 2.5g = (2.5 / 217.045) mol = 0.0115 mol theoretical yield (I asked the demonstrator at the start of the class if x was 4 (from my pre-lab reading, I thought that was most likely) & he said no, it was fewer than that, so I've just worked out x = 1,2,3 for the product.) Product: Molar mass VO(C5H7O2)2 = 265.157 g mol-1 1.66 g yielded = (1.66 / 265.157) mol = 0.00626 mol yielded This is far less than any of the possibilities given above. Am I screwed? Can I extract anything meaningful from that result? Thanks in advance for any help.