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Secure | https://session.masteringchemistry.com/myct/itemview?assignmentProblem ID:92850257 Exercise 7.41 Rescurce prevlous| 22 of 31 next Exercise 7 41 Part A Hydrobromic acid dissolves solid iron according to the following reaction Fe(s)+ 2 HBr(ag) FeBr2(aq) + H2(a) What mass of HBr (in g) would you need to dissolve a 3.2-g pure iron bar on a padlock? Express your answer using two significant figures. , m= Submit My Answers Give Up Part B What mass of H2 would be produced by the complete reaction of the iron bar? Express your answer using two significant figures Submit My Answers Give Up Continue

Explanation / Answer

Molar mass of Fe = 55.85 g/mol

mass of Fe = 3.2 g

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

= 3.2/55.85

= 0.0573 mol

A)

From balanced chemical reaction, we see that

when 1 mol of Fe reacts, 2 mol of HBr is reacting

mol of HBr raecting = (2/1)* moles of Fe

= (2/1)*0.0573

= 0.1146 mol

Molar mass of HBr = 1*MM(H) + 1*MM(Br)

= 1*1.008 + 1*79.9

= 80.908 g/mol

mass of HBr = number of mol * molar mass

= 0.1146*80.908

= 9.2715 g

Answer: 9.3 g

B)

From balanced chemical reaction, we see that

when 1 mol of Fe reacts, 1 mol of H2 is formed

mol of H2 formed = moles of Fe

= 0.0573 mol

Molar mass of H2 = 2.016 g/mol

mass of H2 = number of mol * molar mass

= 0.0573*2.016

= 0.1155 g

Answer: = 0.12 g

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