According to the query of Xia Qing Education Network, the topic is to fill in the relative atomic mass or relative molecular mass (1) aluminum of the following substances; (2) urea [co (NH2) 2]; (3) Potassium chlorate. The answer is that the relative atomic mass of (1) aluminum is 27; (2) The relative atomic mass of urea [CO(NH2)2] is12+16+14+2× 2 = 60; (3) The relative atomic mass of potassium chlorate is: 39+35.5+16× 3 =122.5. So the answer is: (1) 27; (2)60; (3) 122.5。 Therefore, the relative atomic mass of potassium chlorate is 122.5.