August 2002  Chemistry Regents #41-50

Other Regents Exams

Highlight to reveal answers and explanations

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

 

Questions

AnswerExplanations
41 According to Table I, which potential energy diagram
best represents the reaction that forms
H2O(l) from its elements?

1DH is negative, exothermic
42 Which structural formula is incorrect?4central carbon is bonded 5 times
4add 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

4since it is a liquid at 60°C it must boil at a higher temp
45 When 50. milliliters of an HNO3 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
2MV=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
3Table S
22 balance it
48 One hundred grams of water is saturated with
NH4Cl at 50°C. According to Table G, if the
temperature is lowered to 10°C, what is the total
amount of NH4Cl that will precipitate?
(1) 5.0 g     (3) 30. g
(2) 17 g      (4) 50. g
2subtract the amount at 50C from the amount at 10C

52-34= 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
32 parter  M=mol/L

mol=grams /gram formula mass

50 Given the reaction:
2 H2(g) + O2(g)-->2 H2O(l) + 571.6 kJ
What is the approximate DH for the formation of
1 mole of H2O(l)?
(1) .285.8 kJ     (3) .571.6 kJ
(2) +285.8 kJ    (4) +571.6 kJ
1DH is negative exothermic

for 1 mole 285.6kJ is released

that reaction is for 2 moles of water

Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50
 
Back to Regents Exams