June 2013 Chemistry Regents #83-85

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

Question 51-53 Questions 54-56 Questions 57-59 Questions 60-62 Questions 63-65 Questions 66-69 Questions 70-73 Questions 74-77  Questions 78-80  Questions 81-82  Questions 83-85

 

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Base your answers to questions 83 through 85  on the information below.

Chemical concepts are applied in candy making. A recipe for making lollipops is shown below.

Hard-Candy Lollipops Recipe

Ingredients:

414 grams of sugar

177 grams of water

158 milliliters of light corn syrup

Step 1: In a saucepan, mix the sugar and water. Heat this mixture, while stirring, until all of the sugar dissolves.

Step 2: Add the corn syrup and heat the mixture until it boils.

Step 3: Continue boiling the mixture until the temperature reaches 143C at standard pressure.

Step 4: Remove the pan from the heat and allow it to stand until the bubbling stops.

Pour the mixture into lollipop molds that have been coated with cooking oil spray.

83 Explain, in terms of the polarity of sugar molecules, why the sugar dissolves in water. [1]

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The polarity or sugar molecules is similar to the polarity or water molecules.

Both substances consist of polar molecules.

84 Determine the concentration, expressed as percent by mass, of the sugar dissolved in the mixture produced in step 1. [1]

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70.1 %. Significant figures do not need to he shown

work    (414g/(414g +177g)) x 100%

 

85 Explain, in terms of the concentration of sugar molecules, why the boiling point of the mixture in step 3 increases as water evaporates from the mixture. [1]

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The boiling point of the mixture increases as water evaporates because the concentration or dissolved molecules increases.

An increase in the concentration of sugar particles increases the boiling point.

 

Raw score  (out of 85)

Grade
79 90
75 85
50 65

 

 

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

Question 51-53 Questions 54-56 Questions 57-59 Questions 60-62 Questions 63-65 Questions 66-69 Questions 70-73 Questions 74-77  Questions 78-80  Questions 81-82  Questions 83-85

 
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