How many Sc atoms are there in a 14.3 gram sample of Sc ?

Answer 1

First, we need to calculate how many moles there are in 14.3 grams. We do that using the molar mass that we look up on the Periodic Table.

On the Periodic Chart, Scandium is found here:

The molar mass is 44.958 meaning the mass of 1 mole is 44.956 grams. So 14.3/44.958 = 0.31807 moles.

Then, using Avogadro's number, we know that there are 6.02214 x 10²³ atoms per mole which means that there are (0.31807)(6.02214 x 10²³) or 1.92 x 10²³ atoms in 14.3 grams of Scandium. Notice that we round to 3 significant figures because the initial given value (14.3) has 3 sig figs.

Answer 2

Convert grams of Sc to moles of Sc using Molar Mass

Convert moles of Sc to atoms of Sc using Avogadro's number