How many grams of magnesium contain the same number of atoms as 16.2g of calcium?

Answer 1

I assume you mean 40.59 grams of aluminum.

40.59 grams Al (1 mole Al/26.98 grams)(6.022 X 10^23/1 mole Al)

= 9.05978 X 10^23 atoms in that mass aluminum

9.05978 X 10^23 atoms (1 mole Mg/6.022 X 10^23)(24.31 grams/1mole Mg)

= 36.57 grams of magnesium

Answer 2

One way to look at this is to realize that 6g of C is half a mole of carbon. You automatically realize that that half a mole of Mg will give you the same number of Mg atoms as half a mole of C. Your answer is half a mole or the Atomic Mass of Mg in grams divided in half or approximately 12.15g.

You can also solve this using the factor label method. Learning this method will help ( if you plan to continue in Chemistry. In this method, you set up a mathematical problem. 6gC (1 mole C/12 g C) (24.3g Mg/1mole Mg) = 12g Mg

Remember Chemists deal with moles. A mole is 6.02 X1023. The mass number of an element equals the mass of one atom in atomic mass units or the mass of one mole of that element in grams. Remember to check for significant figures.

Answer 3

16.2 g Ca (6.02 x 1023 at / 40.08 g) = 2.43 x 1023 atoms 2.43 x 1023 at Mg (24.31 g / 6.02 x 1023 at) = 9.81 grams