Page 270 - Chemistry eBook

Part B–2
Answer all questions in this part.
Sample Regents Questions
Directions (51–65): Record your answers in the spaces provided in your answer booklet. Some questions may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry.
51 What is the mass of KNO3(s) that must dissolve in 100. grams of water to form a saturated solution at 50.°C? [1]
Base your answers to questions 52 through 55 on the information below.
The reaction between aluminum and an aqueous solution of copper(II) sulfate is represented by the unbalanced equation below.
Al(s) 􏰀 CuSO4(aq) → Al2(SO4)3(aq) 􏰀 Cu(s)
52 Identify the type of chemical reaction represented by the equation. [1]
53 Balance the equation in your answer booklet, using the smallest whole-number coefficients. [1]
54 Explain why the equation represents a chemical change. [1]
June 2012 #51
Answer: 84 grams.
(Any answer from 82 to 86 is acceptable.)
Base your answers to questions 56 through 59 on the information below.
1. On Reffy, Table G (p. 3), locate 50°C. 2.T5r6acWertihteathpeocihnetmuicpalufnortmiluylaouforhtihtetshoeluKteNinOthleinsoel.ution. [1]
Answer
55 Determine the total mass of Cu produced when 1.08 grams of Al reacts completely with 9.58 grams of CuSO4 to produce 6.85 grams of Al2(SO4)3. [1]
ExplanAattiotnal:of 1.4 moles of sodium nitrate is dissolved in enough water to make 2.0 liters of an aqueous solution. The gram-formula mass of sodium nitrate is 85 grams per mole.
3. Follow the point of intersection point across the graph to the left. The
57 Showanumericalsetupforcalculatingthemassofthesoluteusedtomakethesolution. [1]
solubility is 84 g/100 g water.
58 Compare the boiling point of the solution at standard pressure to the boiling point of H2O at standard pressure. [1]
59 Determine the molarity of the solution. [1]
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269 © UNIT 7: SOLUTIONS / SOLUBILITY