Ответ:

Н2О=2+16=18

СuSO4=63+32+(16*4) =159

H2SiO3=(1*2) +28+(16*3) =78

Ответ:

1)H20

Mr(H20)=1*2+16=18

W(H)= 1*2/18=0,11*100%=11%

W(O)=16*1/18=0,89*100%=89%

2)CuSO4

Mr(CuSO4)=64+32+(16*4)=160

W(Cu)=64*1/160=0,40*100%=40%

W(S)=32*1/160=0,20*100%=20%

W(O)=16*4/160=0,40*100%=40%

3)H2SiO3

Mr(H2SiO3)=(1*2)+28+(16*3)=78

W(H)=1*2/78=0,03*100%=3%

W(Si)=28*1/78=0,36*100%=36%

W(O)=16*3/78=0,61*100%=61%

Объяснение: