Question

2 g dintr-un alcan formeaza prin ardere 3 g apa. Afla masa moleculara a alcanului

Answer 1

formula alcanului CnH2n+2 , cu masa molara  M= 14n+2.g/mol

ecuatia reactiei de ardere

CnH2n+2+ (3n+1)/2  O2---> nCo2 + (n+1) H2O

14n+2 g....................................................(n+1)x18g

2g.......................................................................3g

3x(14n+2)= 36(n+1)

42n+6= 36n+36---> 6n=30--> n=5    pentan