How many moles are in 6.99 x 1020 formula units of magnesium bromide (MgBr2) ? Round your answer to 2 decimal places and, if needed, enter scientific notation like this 6.02e23 (would mean 6.02 x 1023.)

1.16x10^-3 mole

Explanation:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02x10^23 formula units. This implies that 1 mole of MgBr2 also contains 6.02x10^23 formula units.

Now, if 1 mole of MgBr2 contains 6.02x10^23 formula units,

Then Xmol of MgBr2 will contain 6.99x10^20 formula units i. e

Xmol of MgBr2 = 6.99x10^20/6.02x10^23

Xmol of MgBr2 = 1.16x10^-3 mole