New York State Earth Science RegentsNew York State Living Environment Regents

 
Nuclear Chemistry
Chemistry Regents June 2006 - Question 49 PDF Print E-mail
chemjun06q49

chemjun06q49-answer
Last Updated on Wednesday, 23 December 2009 16:47
 
Chemistry Regents June 2006 - Question 30 PDF Print E-mail
chemjun06q30

Correct answer: (1) α

Why?:

Nuclear reactions occur in the nuclei of atoms. They make the atom more stable by releasing energy and emitting particles. The particles are alpha (α), beta (β- and β+), and gamma (γ). They are named as such due to lack of words to call them during the time of their discovery. The alpha particle is also known as the helium atom because it has a mass number of 4 and a charge of +2, resembling that of a helium atom. The beta particles are of two kinds, the positively and negatively charged. The positively charged beta particle is also known as an electron because it has a charge of -1 and negligible mass. The positively charged beta particle is the same as the electron but with a charge of +1. It is called a positron. The gamma particles are highly penetrating nuclear emission with no charge and no mass.

Answering this question:

It is important to remember that of all the radioactive particles emitted by a nuclear reaction, it is only the alpha particle that has a mass. The masses of all the rest are negligible. With this, the correct answer can be immediately chosen.

So this leaves us with (1) as the correct answer.

 
Chemistry Regents June 2006 - Question 29 PDF Print E-mail
chemjun06q29

Correct answer: (4) transmutation

Why?:

Conversion of one element to another element is only accomplished through a nuclear reaction. This is not done in any ordinary chemical reactions. Chemical reactions only "touch" the surroundings of the nucleus. This is because chemical reactions involve the release, gain, or sharing of electrons. And the electrons are located around the nucleus, not inside it. Since it is the nucleus that holds the identity of an element, a chemical reaction cannot change its identity. Nuclear reactions on the other hand are reactions occurring in the nucleus. This changes an element's identity. This converts an element to a different element that is more stable.

Answering this question:

You can start by recalling the definitions of each of the processes. Neutralization is the reaction between an acid and a base. This produces salt and water. An example would be the reaction between HCl and NaOH to produce NaCl and H2O.

HCl + NaOH → NaCl + H2O

It can be observed that the same kinds of elements on the reactant side are still present on the product side of the reaction. Thus, no new element is produced. The same is true with a substitution process. A substitution reaction involves the replacement of an atom by another atom. The original atom is not converted into a new atom. It would appear on the product side of the reaction as the same kind of atom. Polymerization is the process of connecting molecules together to form a long chain of molecules called polymers. No new element is formed. Transmutation is the conversion of one atom to another kind of atom. This is done by nuclear reactions such as radioactive decay.

So the correct answer is (4).

 
Chemistry Regents June 2006 - Question 28 PDF Print E-mail
User Rating: / 2
PoorBest 
chemjun06q28

chemjun06q28-ans1

chemjun06q28-answer 2


Last Updated on Wednesday, 23 December 2009 16:51
 
Chemistry Regents June 2006 - Question 27 PDF Print E-mail

chemjun06q27

Correct answer: (4) C-14 and N-16

Why?:

Radioactive decay involves the conversion of a less stable nucleus to a more stable one. This is done by emission of radiation and ionizing particles. In the periodic table, carbon has an atomic mass of 12 amu. That of nitrogen is 14. If some isotopes of an element exist, the atomic mass of that element in the periodic table is very close to the most stable isotope. In this case, C-12 and N-14 are both stable. This simply means that their radioactive decay is not as spontaneous as when their other isotopes undergo decay. Some isotopes of carbon are C-12, C-13, and C-14. Those of nitrogen are N-13, N-14, and N-15.

Answering this question:

Knowing the atomic masses of nitrogen and carbon in the periodic table, it will give us an idea that C-12 and N-14 are more stable than their other isotopes. And these stable isotopes are less likely to undergo spontaneous decay. From the choices, we can then eliminate (1), (2), and (3) because each of them consists of at least one stable isotope.

So the correct answer is (4).

Last Updated on Wednesday, 23 December 2009 15:28
 


Copyright Information

All works and materials contained within this site Copyright © 2009 Technology Strategies For Success

Disclaimer

We are not affiliated with, nor endorsed by, the New York State Education Department.

The information contained in this website is for general information purposes only. The information is provided by "Technology Strategies for Success" and while we strive to keep the information up-to-date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk.