2.1.5 Stoichiometric equation and the extent of a reaction stoichiometric equation: aA+bB→yY+zZ→0=-aA-bB+yY+zZ 0=∑ygB V B -stoichiometric number of substance B vA=-a,vB=-b,vy=y, V7=Z extent of reaction(5,Zeta发音)：反应进展的程度 5= △nB_nB(5)-nB(O) the unit ofξis mol VB VB2.1.5 Stoichiometric equation and the extent of a reaction ν B — stoichiometric number of substance B stoichiometric equation： ν A= -a ， ν B= -b ， ν Y= y ， ν Z= z B B B B B ( ) ( 0 ) ν ξ ν ξ n n − n = Δ = extent of reaction ( ξ, Zeta发音 )：反应进展的程度 the unit of ξ is mol = ∑ + → + B 0 B B A B Y Z ν a b y z 0 = − a A − b B + y Y + z Z