Maybe my school is different, but don’t you have to find the energy required to also heat up the water to boiling point to start? Like include the mC🔺T equation?
How would someone calculate the needed heat to evaporate a solution of 35%hydrogen peroxide? Do i have to split the equations for water & for hydrogen peroxide because they have diffrent boiling points ?
@@ProfessorDaveExplains Oh Prof Dave ! You presented the exercise like an exam question and you stressed the data you were supplying at the start and then the molar mass of water just appeared without comment. The uninitiated would be justified in thinking it was something they ought to know and would just say "this science stuff is too hard" and give up. I suppose I'm whinging at length that you should have put on the data slide.
all chemistry exams provide a periodic table for reference. also, anyone who has studied chemistry for more than a month has the molecular mass of water memorized.
@@ProfessorDaveExplains Point taken but it's 50 years since I for one did a chemistry exam and RU-vidrs (as a general audience) do need it on a plate as I'm sure you must realise from your recent skirmish with the Flat Earth fraternity.
Well they are a special breed of stupid, they’re not taking any chemistry tests. Anyone intelligent enough to study chemistry can google “molar mass water”.
hello Sir may i ask why did you use molar value to be multiplied by delta H instead of using the mass itself? most formulas for heat indicate the m, not mol. and i think this is confusing for introductory students like me.
the units for delta H are kJ/mol in the case he showed. so when you multiply by moles, then kJ/mol * moles will give you kilojoules. mass is generally used for specific heat capacity, not for delta H of vaporization
Hello teach, I went to you do one exercise that have the topic: Approximate f(7π/8) for f(x)=x^2cosx by using the Taylor polynomial of degree 2, centered at c=π. Help me pleace 🙏
