Since the oxygen gas evolved is collected over water, the volume at each stage is assumed to include 2.5% water vapour. A correction must be applied in mL Gas buret reading= 2.80 mL

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .