Question

Determinati  concenttratia  molara a solutiilor care contin:
a)400g NaOH in 5L solutie;
b)196 g H2SO4 in 200g solutie cu p =1,84 g/cm cub.

Answer 1

a)cM=nr moli/V=masa substanta/(masa molara substanta * volum)
cM=400/(40*5)=2M
b)c%=md/ms*100=196/200*100=98%
cM=c%*ro*10/masa molara H2SO4 = 98*10*1,84/98=>cM=18.4 moli/litru

sau daca nu stii formula asta folosesti varianta 2

ro = m/v=>V=m/ro=200/1,84=108,69 ml(cm cubi) = 0,10869 litri
cM=nr moli/v=masa acid/(masa molara acid * V)=196/(98*10869)=18,4 moli/litru