Ответы и объяснения

2013-01-15T20:52:31+04:00

Al2S3
M(S) = 32*3= 96
M(Al) = 27*2=44
M(Al2S3) = 96+44=140
w(S) = 96/140*100%=31%
w(Al) = 44/140*100%=69%