Portage learning chem 103 module 6 exam questions with complete answers

Portage Learning - CHEM 103 MODULE 6 Exam


CHEM 103 ff




MODULE 6 2022 ff ff




Question 1 ff




Not yet graded / 10 pts
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Click this link to access the Periodic Table. This may be helpful
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throughout the exam.
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List and explain if each of the following solutions conducts an electric
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current: sodium chloride (NaCl), hydrochloric acid (HCl) and sugar
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(C6H12O6).
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Sodium chloride (NaCl) is an ionic compound and conducts since it
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forms ions in solution. Hydrochloric acid (HCl) is a polar compound and
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conducts since it forms ions in solution. Sugar (C6H12O6) is a molecular
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compound but does not form ions in solution so it does not conduct.
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Question 2 ff




Not yet graded / 10 pts
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Explain how and why the presence of a solute affects the boiling point of a
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solvent.
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The presence of a solute raises the boiling point of a solvent by
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lowering the vapor pressure of the solvent. With this lower vapor
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pressure, more heat (a higher boiling point) is required to raise the
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vapor pressure to atmospheric pressure.
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Question 3 ff




Not yet graded / 10 pts
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Click this link to access the Periodic Table. This may be helpful
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throughout the exam.
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, Rank and explain how the freezing point of 0.100 m solutions of the
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following ionic electrolytes compare, List from lowest freezing point to
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highest freezing point.
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GaCl3, Al2(SO4)3, NaI, MgCl2 ff ff ff




Your Answer: ff




Al2(SO4)3 -> 2Al3+, 3SO4 -2 = = 5 ions -> most ions = lowest ff ff ff ff
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freezing point
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GaCl2 -> Ga3+, Cl- ff ff ff
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= 4 ions ff ff




ff MgCl2 = 3 ions ff ff ff




NaI = 2 ions - > least ions = highest freezing point
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GaCl3 → Ga+3 + 3 Cl- ff
∆tf = 1.86 x 0.1 x 4 =
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3rd lowest FP
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3 SO4 ff


Al2(SO4)3 → 2 Al+3 +
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-3
∆tf = 1.86 x 0.1 x 5ff ff ff ff ff ff




lowest FP ff =
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NaI → Na+ + I- ∆tf = 1.86 x 0.1 x 2 ff ff ff ff ff ff



= highest FP
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MgCl2 → Mg+2 + 2 Cl- ∆tf = 1.86 x 0.1 x 3 ff ff ff ff ff ff



= 2nd lowest FP
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FP: Al2(SO4)3 < GaCl3 < MgCl2 < NaI ff ff ff ff ff ff




Question 4 ff




Not yet graded / 10 pts
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Click this link to access the Periodic Table. This may be helpful
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throughout the exam.
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Show the calculation of the mass percent solute in a solution of 20.8
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grams of Ba(NO3)2 in 400 grams of water. Report your answer to 3
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significant figures.
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