Chapter 24

Chapter 24 - CHAPTER 24 NUCLEAR REACTIONS AND THEIR...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
24-1 CHAPTER 24 NUCLEAR REACTIONS AND THEIR APPLICATIONS 24.1 a) Chemical reactions are accompanied by relatively small changes in energy while nuclear reactions are accompanied by relatively large changes in energy. b) Increasing temperature increases the rate of a chemical reaction but has no effect on a nuclear reaction. c) Both chemical and nuclear reaction rates increase with higher reactant concentrations. d) If the reactant is limiting in a chemical reaction, then more reactant produces more product and the yield increases in a chemical reaction. The presence of more radioactive reagent results in more decay product, so a higher reactant concentration increases the yield in a nuclear reaction. 24.2 a) The percentage of sulfur atoms that are sulfur-32 is 95.02%, the same as the relative abundance of 32 S. b) The atomic mass is larger than the isotopic mass of 32 S. Sulfur-32 is the lightest isotope, as stated in the problem, so the other 5% of sulfur atoms are heavier than 31.972070 amu. The average mass of all the sulfur atoms will therefore be greater than the mass of a sulfur-32 atom. 24.3 a) She found that the intensity of emitted radiation is directly proportional to the concentration of the element in the various samples, not to the nature of the compound in which the element occurs. b) She found that certain uranium minerals were more radioactive than pure uranium, which implied that they contained traces of one or more as yet unknown, highly radioactive elements. Pitchblende is the principal ore of uranium. 24.4 Radioactive decay that produces a different element requires a change in atomic number ( Z , number of protons). X A Z A = mass number (protons + neutrons) Z = number of protons (positive charge) X = symbol for the particle N = A - Z (number of neutrons) a) Alpha decay produces an atom of a different element, i.e., a daughter with two less protons and two less neutrons. X A Z Y 4 A 2 Z + He 4 2 2 fewer protons, 2 fewer neutrons b) Beta decay produces an atom of a different element, i.e., a daughter with one more proton and one less neutron. A neutron is converted to a proton and β particle in this type of decay. X A Z Y A 1 Z + + β 0 1 1 more proton, 1 less neutron c) Gamma decay does not produce an atom of a different element and Z and N remain unchanged. * X A Z X A Z + γ 0 0 (* X A Z = energy rich state), no change in number of protons or neutrons. d) Positron emission produces an atom of a different element, i.e., a daughter with one less proton and one more neutron. A proton is converted into a neutron and positron in this type of decay. X A Z Y A 1 Z + β + 0 1 1 less proton, 1 more neutron e) Electron capture produces an atom of a different element, i.e., a daughter with one less proton and one more neutron. The net result of electron capture is the same as positron emission, but the two processes are different.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 26

Chapter 24 - CHAPTER 24 NUCLEAR REACTIONS AND THEIR...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online