(2) According to the chemical formula C 1 2H2O 14Zn of zinc gluconate, 1 zinc gluconate molecule contains 12 carbon atoms, 22 hydrogen atoms,14 oxygen atoms and1zinc atoms, *. So the answer is: 49;

(3) According to the chemical formula C 12H22O 14Zn of zinc gluconate, the atomic number ratio of carbon, hydrogen, oxygen and zinc in zinc gluconate is12: 22:14:1; So the answer is:12: 22:14:1;

(4) The relative molecular weight of zinc gluconate is12×12+122+16×14+65 = 455; So the answer is: 455;

(5) The mass ratio of carbon, hydrogen and oxygen in zinc gluconate =12×12:1× 22:16×14 =144: 22: 222. So the answer is: 72:11:112;

(6) According to the mass fraction of elements in the compound = relative atomic mass × atomic number relative molecular mass × 100%, the mass fraction of hydrogen in zinc gluconate is:1× 22455×100% ≈ 4.8%; So the answer is: 4.8%;

(7) The mass of carbon in 91g zinc gluconate is 91g×12×12455×100% = 28.8g; Therefore, the answer is: 28.8g；;

(8) The mass of zinc gluconate containing 56 grams of oxygen is 56 g16×14455×100% =113.75 g; So the answer is:113.75;

(9) According to the label information, the mass fraction of zinc in each oral liquid is: 5 mg10g×100% = 0.05%; So the answer is: 0.05%;

(10) Children 1kg body weight need 0.5mg zinc per day, and children weighing 20kg need 0.5 mg× 20kg zinc1kg =10mg zinc per day; Half of them are provided by oral liquid, so it is necessary to supplement 5 mg of zinc through the oral liquid every day; According to the label, each oral liquid contains 5mg of zinc, so the child has to take the oral liquid 1 tablet every day. Therefore, the answer is:1.