
August 2002 Chemistry Regents #4150
Highlight to reveal answers and explanations
Questions 110 Questions 1120 Questions 2130 Questions 3140 Questions 4150 

Questions 
Answer  Explanations 
41 According to Table I, which potential energy diagram best represents the reaction that forms H_{2}O_{(l)} from its elements?

1  DH is negative, exothermic 
42 Which structural formula is incorrect?  4  central carbon is bonded 5 times 
4  add the top number and bottom numbers  
44 The vapor pressure of a liquid is 0.92 atm at 60°C. The normal boiling point of the liquid could be (1) 35°C (3) 55°C (2) 45°C (4) 65°C 
4  since it is a liquid at 60°C it must boil at a higher temp 
45 When 50. milliliters of an HNO_{3} solution is exactly neutralized by 150 milliliters of a 0.50 M solution of KOH, what is the concentration of HNO3? (1) 1.0 M (3) 3.0 M (2) 1.5 M (4) 0.5 M 
2  MV=MV (150mL x 0.50M)/50mL = 
46 In Period 3, from left to right in order, each
successive element will (1) decrease in electronegativity (2) decrease in atomic mass (3) increase in number of protons (4) increase in metallic character 
3  Table S 
2  2 balance it  
48 One hundred grams of water is saturated with NH_{4}Cl at 50°C. According to Table G, if the temperature is lowered to 10°C, what is the total amount of NH_{4}Cl that will precipitate? (1) 5.0 g (3) 30. g (2) 17 g (4) 50. g 
2  subtract the amount at 50C from the
amount at 10C 5234= 18grams close enough 
49 What is the total number of grams of NaI_{(s)} needed to make 1.0 liter of a 0.010 M solution? (1) 0.015 (3) 1.5 (2) 0.15 (4) 15 
3  2 parter M=mol/L mol=grams /gram formula mass 
50 Given the reaction: 2 H_{2(g)} + O_{2(g)}>2 H_{2}O_{(l)} + 571.6 kJ What is the approximate DH for the formation of 1 mole of H_{2}O(l)? (1) .285.8 kJ (3) .571.6 kJ (2) +285.8 kJ (4) +571.6 kJ 
1  DH is
negative exothermic for 1 mole 285.6kJ is released that reaction is for 2 moles of water 
Questions 110 Questions 1120 Questions 2130 Questions 3140 Questions 4150
