Question

how many atoms are in 161 grams of calcium

Answer 1

First you have to work out the number of moles of calcium there are and to do this you use the following equation: moles = mass/atomic weight.

So you calculate: 161g/40.078mol/g = 4.017moles.

Then you work out the number of atoms by multiplying your moles by 'Avagadro's constant' which is 6 x 10^23':

4.017*(6 x 10^23) = 2.410 x 10^24 atoms in 161g of calcium