Question

an atom of magnesium weighs 3.98×10/-23 g. calculate the number of atoms in 12 g of magnesium.
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Answer 1

We know that, 1 mole of Magnesium weighs 12 g

→ 1 mole = 24 g

→ 1 mole = 6.023 x 1023 atoms = 24 g

According to question we are required to

find how much 1 atom weighs.

→ 6.023 × 1023 atoms → 24 g :: 1 atom → x

Product of means = Product of Extremes

Vol 4G 2.2% LTE

⇒ x = 24 g / 6.023 × 10²3

⇒ x = 3.98 × 10-23 g

Hence the mass of one atom of Mg is 3.98 × 10-23 g.