Question

Calculate the no. Of aluminium atoms in a piece of aluminium rod weighing 5gram

Answer 1

The GFM of an aluminium atom is 26.982 g per mole. A mole is 6.022  * 10^23 atoms. We are given that the aluminum rod weighs 5 grams so we can create a ratio,

1 mole              x mole

------------       =  ------------      

26.982g                5g

This can be cross multiplied to get

26.982g * x mole = 5 g * 1 mole

We then isolate x to get

x mole = (5g*1mole) / 26.982g

x mole = 0.18531 moles

Then we multiply by Avogadro's number, 6.022 * 10^23 which gives us the number of atoms in an aluminum rod.

0.18531 * 6.022 * 10^23 = 1.11593682 * 10^23