Chapter 25 Chemistry Review Questions

CHAPTER 25 CHEMISTRY REVIEW QUESTIONS

21 The initial mass of a radioisotope is 10.0 g. If the radioisotope has a half-life of 2.75 years, how much remains after four half-lives?

24 Graphing A sample of polonium-214 originally has a mass of 1.0 g. Express the mass of polonium-214 remaining as a percent of the original sample after a period of one, two, and three half-lives. Graph the percent remaining versus the number of half-lives. Approximately how much time has elapsed when 20% of the original sample remains? Each half-life corresponds to a 50% reduction in the amount remaining.

37 Compare and contrast chemical reactions and nuclear reactions in terms of energy changes and the particles involved.

38 Match each numbered choice on the right with the correct radiation type on the left. (25.1) a. alpha 1. high speed electron s 2. 2+ charge 3. no charge 4. helium nucleus 5. blocked very easily b. beta 6. electromagnetic radiation c. gamma 39 What is a nucleon? 40 What is the difference between a positron and an electron? 41 Describe the differences between a balanced nuclear equation and a balanced chemical equation. 42 What is the strong nuclear force? On what particles does it act? 49 Why are some radioisotopes found in nature, while others are not?

Thinking problem 49 Why are some radioisotopes found in nature, while others are not? 87 Write a balanced nuclear equation for the positron emission of nitrogen-13. (Positron is an electron with +1 charge)

Take home quiz 69 Complete the following equations:

70 Write a balanced nuclear equation for the alpha decay of americium-241.

71 Write a balanced nuclear equation for the beta decay of bromine-84.

72 Write a balanced nuclear equation for the beta decay of selenium-75.

77 The half-life of tritium (Hydrogen-3) is 12.3 years. If 48.0 mg of tritium is released from a nuclear power plant during the course of a mishap, what mass of the nuclide will remain after 49.2 years? After 98.4 years?

78 Technetium-104 has a half-life of 18.0 minutes. How much of a 165.0 g sample remains after 90.0 minutes?

101 Identify each of the following as a chemical property or a physical property. a) The element mercury has a high density. c. Zinc oxidizes when exposed to air. b. Solid carbon dioxide sublimes at room temperature. d. Sucrose is a white crystalline solid. 105 If the volume of a sample of chlorine gas is 4.5 L at 0.65 atm and 321 K, what volume will the gas occupy at STP?

106 The temperature of 756 g of water in a calorimeter increases from 23.2°C to 37.6°C. How much heat was given off by the reaction in the calorimeter?