August 2016 Chemistry Regents #77-80

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Questions 1-5 Questions 6-10 Questions 11-15 Questions 16-20 Questions 21-25 Questions 26-30 Questions 31-35 Questions 36-40 Questions 41-45 Questions 46-50

Questions 51-53 Questions 54-55 Questions 56-59 Questions 60-63 Questions 64-65 Questions 66-69 Questions 70-73 Questions 74-76  Questions 77-80  Questions 81-85

 

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Question 77-80

 

 

Base your answers to questions 77 and 80 on the information below and on your knowledge of chemistry.

A company produces a colorless vinegar that is 5.0%  HC2H3O2 in water. Using thymol blue as an indicator, a student titrates a 15.0-milliliter sample of the vinegar with 43.1 milliliters of a 0.30 M NaOH(aq) solution until the acid is neutralized.

77 Based on Table M, what is the color of the indicator in the vinegar solution before any base is added? [1]

Answer-->yellow

78 Identify the negative ion in the NaOH(aq) used in this titration. [1]

Answer--> OH- or hydroxide.

79 The concentration of the base used in this titration is expressed to what number of significant figures? [1]

Answer--> 2

80 Determine the molarity of the HC2H3O2 in the vinegar sample, using the titration data. [1]

Answer-->  0.86M

on to Questions 81-85

 

 

Questions 1-5 Questions 6-10 Questions 11-15 Questions 16-20 Questions 21-25 Questions 26-30 Questions 31-35 Questions 36-40 Questions 41-45 Questions 46-50

Questions 51-53 Questions 54-55 Questions 56-59 Questions 60-63 Questions 64-65 Questions 66-69 Questions 70-73 Questions 74-76  Questions 77-80  Questions 81-85

 

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