A mixture of MgBr2 and inert material is analyzed to determine the Mg content. First the mixture is dissolved in water. Then all of the bromide ion is precipitated as AgBr by the addition of an excess of silver nitrate. MgBr2(aq) + 2AgNO3(aq) 2AgBr(s) + Mg(NO3)2(aq) In one experiment, a 0.8107 g sample of the mixture resulted in 1.1739 g of AgBr. Determine the percent (by mass) of Mg in the mixture.

9.24% the percent of Mg in the mixture.

Explanation:

Mass of silver bromide = 1.1739 g

Moles of silver bromide =

1 mole of AgBr has 1 mole of bromine atom.Then 0.006244 moles AgBr has 0.006244 mole bromine atom.

Moles of bromine atoms = 0.006244 moles

Magnesium bromide has 2 moles of bromine atom.Then 0.006244 moles of bromine atoms will be in :

Magnesium bromide has 1 mole magnesium atom, then 0.003122 moles of magnesium bromide will have :

magnesium atom

Mass of 0.003122 moles of magnesium :

0.003122 mol × 24 g/mol = 0.07493 g

Mass of the sample = 0.8107 g

Percentage of magnesium in the sample ;

9.24% the percent of Mg in the mixture.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

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