Question

The percent composition by mass of magnesium MgBr2 (gram formula mass= 184 grams/mole) is equal to...

a- 24/184 x 100
b- 160/184 x 100
c- 184/24 x 100
d- 184/160 x 100

PLEASE I REALLY NEED AN ANSWER FOR THIS QUESTION!!!

Answer 1

A is correct

Mg - 24.31
Br - 79.90x2 - 184.11
24/184x100 gives you the percent

Answer 2

Answer : The correct option is, (a)
`(24)/(184)* 100`

Solution : Given,

Molar mass of
`MgBr_2` = 184 g/mole

Molar mass of Mg = 24 g/mole

Formula used :

`\%\text{ Composition of Mg}=\frac{\text{Molar mass of Mg}}{\text{Molar mass of }MgBr_2}* 100`

Now put all the given values in this formula, we get the percent composition of magnesium.

`\%\text{ Composition of Mg}=(24g/mole)/(184g/mole)* 100`

`\%\text{ Composition of Mg}=(24)/(184)* 100`

Therefore, the correct answer is, (a)