How many grams of Br2 are needed to form 67.1 g of AlBr3 ?

2Al(s)+3Br2(l)⟶2AlBr3(s)

Approximately .

Explanation:

Look up the relative atomic mass of and on a modern periodic table:

Calculate the formula mass of and :

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Calculate the number of moles of formula units in of :

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Refer to the balanced equation for this reaction. The ratio between the coefficients of and in that equation is three-to-two. That corresponds to the ratio:

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It is already calculated that approximately of was produced through this reaction. Apply this ratio to approximate the (minimum) number of moles of that is consumed:

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Calculate the mass of that of :

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