Answer to Question #144064 in General Chemistry for Shyla

Question

1. Nickel makes up 25% of the total mass of a fifty pence coin. A fifty pence coin has a mass of 8.0 g.

(i) Calculate how many moles of nickel atoms are in a fifty pence coin.

Answer 1

Well firstly you need to find out how much of the actual coin is nickel:

8 x 0.25 = 2g

Then you go the periodic table, and find out the Mr (Atomic weight) of Nickel, it's 58.69. That means that if you have 58.69g of Nickel, you have 1mol. We don't have 58.69, we've got only 2! So to find the amount of mol of nickel, you simply divide the mass that you have (2) by the Mr (58.69).

2 / 58.69 = 0.034mol of Nickel.