1H3AsO4 + 1Mg(OH)2 = …

1) cacl2+h2so4=caso4 + 2hcl

2) cacl2 + h2co3=caco3 + 2hcl

3) 3cacl2 + 2h3po4 = ca3(po4)2 + 6hcl

4) cacl2 +2naoh = ca(oh)2 + 2nacl

5)  cacl2+h2so4=caso4 + 2hcl

  m(al2s3 )= (27*2)+(32*3)=150

m(cu(oh)2)= (63,5)+(16+1)*2=97,5

m(zn(oh)2co3)=65+(16+1)*2+12+(16*3)=159

m(kal(so4)2)=(39+27+(32+ 16*4)*2)=258

a)h2+cl2=2hcl

b)4p+5o2=2p2o5

с)na2o+2hno3=2nano3+2h2o

cac2 + 2h2o = ca(oh)2 +c2h2

n(c2h2)=2/22.4=0.09 моль

m(cac2)=0.09 * 64 =5.76г - участвовало в реакции

w=(6.4-5.76)/6.4=0.1 или 1% примесей