Question

Question #57b25

Answer 1

Your answer is entirely reasonable. However your answer has too many significant digits 90.4 grams of `Mg_2Si` has only three significant digits so your answer can have only 3 significant digits
None of the answer given seem to be correct.

Explanation:

First find the number of moles of`Mg_2Si`in 90.4 grams of `Mg_2Si`

`2 xx Mg = 2 xx 24 = 48`
`1 xx Si = 1 xx 28 = 28` adding them gives

`48 + 28 = 76 g/m Mg_2Si`

`90.4/76 = 1.19 m.`

1 mole of `Mg_2Si` = 1 mole of `SiH_4`

so 1.19 moles of `Mg_2Si` = 1.19 moles `SiH_4`

`1 Si = 1 xx 28 = 28`
`4 H = 4 xx 1 = 4`

adding them gives 32 g/m `SiH_4`

`1.19 xx 32 g/m = 38.1 g SiH_4`