January 2009 Chemistry Regents #78-79

Highlight to reveal answers and explanations

 

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

Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-66 Questions 67-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-79 Questions 80-81

 

Other Regents Exams

Questions

Base your answers to questions 78 through 79 on the information below.

A substance known as heavy water can be obtained from ordinary water and could be a significant source of energy in the future. Heavy water contains deuterium, H-2. Instead of the two hydrogen atoms in a typical water molecule, a heavy water molecule has two deuterium atoms. In 3.78 kilograms of ordinary water, the percent composition by mass of heavy water is approximately 0.0156%. Deuterium atoms completely ionize at approximately 108 K. The result is an ionized gas consisting of electrons and deuterons (the nuclei of deuterium). A triton is the nucleus of a tritium atom, H-3. These particles react according to the equations below. In the second equation, X represents an unidentified product.

78 Calculate the mass of heavy water in a 3.78-kilogram sample of ordinary water. Your response must include both a correct numerical setup and the calculated result. [2]

HIGHLIGHT TO SEE THE ANSWER

0.0156

X 3.78

100   

(0.000 156)(3.78 kg)

Answer==>0.000 590kg

or 5.90 x 10-4kg

 

79 Identify particle X in the second nuclear equation. Your response must include the symbol, atomic number, and mass number of the particle. [1]

HIGHLIGHT TO SEE THE ANSWER

1 n
0

on to Questions 80-81

 

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

Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-66 Questions 67-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-79 Questions 80-81

 
Back to Regents Exams