question_answer 69)

  Fill in the blanks. (a) In a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is called ......... , (b) A group of atoms carrying a fixed charge on them is called ......... . (c) The formula unit mass of is??. (d) Formula of sodium carbonate is ......... and that of ammonium sulphate is ......... .

Answer:

  (a) In a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is called law of conservation of mass. (b) A group of atoms carrying a fixed charge on them is called polyatomic ion. (c) The formula unit mass ofis 310 g. (d) Formula of sodium carbonate is  and that of ammonium sulphate is . Complete the following crossword puzzle (Figure) by using the name of the chemical elements. Use the data given in the table following.