Question

(B) An element having
Atomic mass of 27u and Atomic number 13
combines with the element having Atomic mass of 16u and atomic number 8.
Write the formula of the compound formed by their combination.
Also calculate the number of ions present in 0.051g of it.​

Answer 1

Answer:

6.022 x 1020

Explanation:

To calculate the number of aluminium ions in 0.051g of aluminium oxide:

1 mole of aluminium oxide = 6.022 x 1023 molecules of aluminium oxide

1 mole of aluminium oxide (Al2O3) = 2 x Mass of aluminium + 3 x Mass of Oxygen

= (2x 27) + (3 x16) = 54 +48 = 102g

1 mole of aluminium oxide = 102g = 6.022 x 1023 molecules of aluminium oxide

Therefore, 0.051g of aluminium oxide has = 0.051 x 6.022 x 1023 / 102

    = 3.011 x 1020 molecules of aluminium oxide

One molecule of aluminium oxide has 2 aluminium ions, hence number of aluminium ions present in 0.051g of aluminium oxide = 2 x 3.011x 1020 molecules of aluminium oxide

= 6.022 x 1020