Cho 2 coc dung dung dich HCL Voi nong do va khoi luong nhu nhau. Them m (gam) Kim loai sat vao Coc Thu nhat thay Co khi hidro thoat ra , them m (gam) muoi vao coc Thu Hai khong Thay co khi bay ra, Khong Thay co ket tua xuat hien. khoi luong dung dich o hai coc co thay doi khong ? Giai thich
