Question #038ae

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Answer 1 · 2018-01-22T17:12:01

54.41 grams.

In general, the mass of a substance can be found from the number of moles by:

#"mass" = "moles" xx "molar mass"#

For #"MgO"#, the molar mass of the molecule can be found by adding up the molar masses of its constituent atoms. That is, (values taken from Google)

#"molar mass"("MgO") = "molar mass"("Mg") + "molar mass"("O")#

#= "24.31 g.mol" + "16.00 g/mol"#

#"= 40.31 g/mol"#

Or, the molar mass of #"MgO"# might often be given to you. Either way,

#"mass" = "moles" xx "molar mass"#

#= "1.350 moles" xx "40.31 g/mol"#

#"= 54.41 g"# (rounded)