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9th Class Science Atoms and Molecules Question Bank 9th CBSE Science Atoms and Molecules

  • question_answer
                    (a) Find the mass of one molecule of water. (b) If 16.26 mg of a sample of an element X contains 1.66 x 1020 atoms. What is the atomic mass of the element X!

    Answer:

       (a) Molar mass of water = 2x1+16=18 g 1 mol =6.022 x 1023 molecules =18 g of water 1 molecule weigh (b) 1 mole of element ^contains =6.022 x1023 atoms 1.66 x 1020 atoms weigh 16.26 mg =16.26 x10-3g 6.022 x 1023 atoms will weigh Therefore, atomic mass of element X is 59 u.


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