1,chat duoc dung de dieu che oxi trong phong thi nghiem la a.H2O b.KMnO4 c.ko khi d.CaCO3 2.tron 20gam dung dich NaOH10% vs 30gam dung dich NaOH15% thi duoc dung dich co nong do phan tram la a.13% b.12,5% c.25% d.5% 3.oxit axit gom tat ca cac chat trong nhom a.CaO,Na2O b.Na2O,N2O5 c.CO2,N2O5 d.Na2O,CO2 4.nhom cac chat sau day gom deu muoi a.CaCO3,MgCl2,CuSO4,NaNO3 b.Na2O,KOH,HCl,FeCl2 c.H2SO4,HNO3,HCl,H2S d.CuCl2,ZnCl2,CaCO3,HCl 5.khi H2 phan ung dc vs tat ca cac chat trong nhom a.CuO,HgO,H2O b.CuO,HgO,O2 C.CuO,HgO,H2SO4 D.CuO,HgO,HCl 6.the tich khi oxi(dktc)can dung de dot chay 9g Cacbon la a.16,8 lit b.84 lit c.21,3 lit d.33,6 lit 7.phan ung nao sau day la phan ung the a.Fe+2HCl->FeCl2+H2 b.Na2O+H2O->2NaOH c.Fe2O3+6HCl->2FeCl3+H2O d.2KClO3->2KCl+O2( có t độ) 8.nong do mol cua 800ml dung dich co hoa tan 20,2 g KNO3 la a,0,5M b.2M c.2,5M d.0,25M 9.quy tim doi sang do khi cho vao lo dung a. dd HCl b.dd NaOH c.dd NaCl d.H2O 10.nhom cac chat sau day deu la bazo a.NaOH,HCl,Ca(OH)2,NaCl b.Ca(OH)2,Al(OH)3,Mg(OH)2,NaOH c.MgCl2,NaHCO3,K2SO4,Ca(NO3)2 d,NaOH,Ca(OH)2,MgO,K2O