Question

16g de Ca de puritate 25% reactioneaza cu 10g de H2O.Sa se afle masa Ca(OH)2 obtinut.Ajutaţi-mă,vă rog!!!

Answer 1

puritatea = m pur / m impur*100 => m pur = puritatea * m impur/100 = 25*16/100=4g Ca

MCa=40g/mol

n=m/M=4/40=0,1 moli Ca

MH2O=18g/mol

n=m/M=0,555 moli H2O

Ca in exces -> 0,1-0,555 => 0,455 moli Ca in exces

Ca + 2H2O --> Ca(OH)2 + H2

2*18g H2O.......................74g Ca(OH)2
10g H2O..........................x=20,555g Ca(OH)2