H2O + H2OSO4
H2SO4 => SO4
H2OSO4 = H
Chemistry – A-level/undergraduate level
This is a frustratingly inconsistent approach to writing chemical formulae. On the one hand the teacher has gone to the trouble of also using structural formulae to improve clarity (eg H2N2O2 could be nitramide, but the addition of HO-N=N-OH makes it clear that we are dealing with hyponitrous acid here), but then writes SI (sulphur iodine) instead of Si (silicon) in the formula for orthosilicic acid. This, combined with not using subscripts for many of the numbers, could lead to a great deal of confusion.
Whilst this lesson appears to be aimed at quite a high level, such elementary errors may affect comprehension.
5/10 - rather sloppy.