Question

please help!

Convert 1.86 x 1025 formula units of Mg(OH)2 to grams.

Answer 1

Answer : The mass of $Mg(OH)_2$ is, 1800.7 grams.

Explanation :

As we know that 1 mole of $Mg(OH)_2$ contains $6.022\times 10^{23}$ atoms

And, 1 mole of $Mg(OH)_2$ has 58.3 g

So, we can say that:

As, $6.022\times 10^{23}$ formula unit of $Mg(OH)_2$ present in 58.3 gram of $Mg(OH)_2$

So, $1.86\times 10^{25}$ formula unit of $Mg(OH)_2$ present in $\frac{1.86\times 10^{25}}{6.022\times 10^{23}}\times 58.3=1800.7$ gram of $Mg(OH)_2$

Therefore, the mass of $Mg(OH)_2$ is, 1800.7 grams.