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for a reactant in solution One way in which the useful metal copper is produced

ID: 304095 • Letter: F

Question

for a reactant in solution One way in which the useful metal copper is produced is by dissolving the mineral azurite, which contains copper(II) carbonate, in concentrated sulfuric acid. The sulfuric acid reacts with the copper(II) carbonate to produce a blue solution of copper(II) sulfate. Scrap iron is then added to this solution, and pure copper metal precipitates out because of the following chemical reaction: Fe(s) + CuSO4(aq) ? Cu(s) + Feso,(aq) Suppose an industrial quality-control chemist analyzes a sample from a copper processing plant in the following way. He adds powdered iron to a 250. mL copper(II) sulfate sample from the plant until no more copper will precipitate. He then washes, dries, and weighs the precipitate, and finds that it has a mass of 134. mg Calculate the original concentration of copper(II) sulfate in the sample. Be sure your answer has the correct number of significant digits.

Explanation / Answer

Molar mass of Cu = 63.55 g/mol

mass of Cu = 0.134 g

mol of Cu = (mass)/(molar mass)

= 0.134/63.55

= 2.109*10^-3 mol

According to balanced equation

mol of CuSO4 reacted = moles of Cu formed

= 2.109*10^-3 mol

Molar mass of CuSO4,

MM = 1*MM(Cu) + 1*MM(S) + 4*MM(O)

= 1*63.55 + 1*32.07 + 4*16.0

= 159.62 g/mol

mass of CuSO4 = number of mol * molar mass

= 2.109*10^-3*1.596*10^2

= 0.3366 g

concentration = mass of CuSO4 / volume in L

= 0.3366 g / 0.250 L

= 1.35 g/L

Answer: 1.35 g/L