Question

Find out the mass of 10^21 molecules of copper

Answer 1

We know that 1 Mole of copper is 63.5g.

Therefore we need to find the number of moles.

Since 1 Mole is 6.022 x 10^23 molecules.

Therefore, 10^21 molecules is 10^21/(6.022 10^23)

i.e 1.66 x 10^(-2) moles.

Hence, mass of 10^21 moles is,

(1.66 x 10^(-2) x 63.5 )

= 0.105 Grams.