Question

1. How many aluminum atoms are there in 98 g of Al2S3?

   1. 7.86 x1023 aluminum atoms

   2. 0.652 aluminum atoms

   3. 5.89 x1025 aluminum atoms

4. 98 x1023 aluminum atoms

Answer 1

To find the number of aluminium (A1) atoms Given that 98 grames of Al2S3 First find the moles of Al2S moles - mass molarm ass molarmass of Al2S3 150.16 g/mol 98g 150.16 g/mol moles - 0.652moles To find the moles of aluminium 1 mole of Al2S3 gives 2 moles of aluminium (A1) So the moles of aluminum = 0.652×2 1.304moles To find the atom Avogadro's constant say s that1mole of any atom contains 6.022 x1023 atom s 1 mole - 6.022x1023 atoms So1.304moles of A1 -1.304x 6.022 x103atoms 7.86x1023 atoms Hence the number of aluminium (Al)atoms 7.86 x1023 atoms