January 2013 Chemistry Regents #62-65

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  Base your answers to questions 62 through 65 on the information below.

Ammonium chloride is dissolved in water to form a 0.10 M NH4Cl(aq) solution. This dissolving process is represented by the equation below.

62 Determine the number of moles of NH4Cl(s) used to produce 2.0 liters of this solution. [1]

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0.20 mol

63 State evidence that indicates the dissolving of ammonium chloride is an endothermic process. [1]

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The process requires heat to dissolve NH4Cl.

Energy is absorbed as NH4Cl dissolves.

The energy term is positive on the left side of the equation arrow.

The heat of reaction is positive.

64 Explain, in terms of ions, why a 10.0-milliliter sample of 0.30 M NH4Cl(aq) is a better conductor of electricity than a 10.0-milliliter sample of the 0.10 M NH4Cl(aq). [1]

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The 0.30 M NH4Cl(aq) sample has more mobile ions in solution.

The 0.10 M NH4Cl solution has a lower concentration of ions.

65 Determine the minimum mass of NH4Cl(s) required to produce a saturated solution in 100. grams of water at 40.°C. [1]

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47 g +/-1 g

(for all the dummies that copy the answers, don't include the +/-1)

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Questions 51 Questions 52-54 Questions 55-58 Questions 59-61 Questions 62-65 Questions 66-69

Questions 70-72 Questions 73-76 Questions 77-79 Questions 80-82 Questions 83-85

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