9 Wash out the 100 cm3 beaker and pour the Th e sea is mainly water but there are lots of other fi ltrate into the beaker. things in it too. Th e most common substance in 10 Boil the liquid again until there is almost none left . seawater is sodium chloride, or common salt. ...
Lesson 1 enzymes-IGCSE解读 Biologicalcatalysts IGCSEBiology(Cambridge) Acatalystisasubstancethatspeedsuptherateofachemicalreactionbutisnotitselfchangedbythereaction.Hydrogenperoxidebreaksdowntowaterandoxygen hydrogenperoxide manganeseoxide water+oxygen 2H2O2 2H2O+ O 2 Theescapingoxygencausesthefoaming A...