Unit 7, Chapter 22 Integrated Science

Unit Seven: Changes in Matter 22.1 Nuclear Reactions 22.2 Carbon Reactions and the Environment Chapter 22 Chemistry and the Environment

Chapter 22 Learning Goals Compare and contrast nuclear reactions with chemical reactions. Describe the environmental impact of nuclear reactions. Research and describe the environmental and economic impact of the end-products of chemical reactions. Identify how personal choices about products can have an impact on the environment. Evaluate the impact of scientific research on society and the environment. Organize data and use it to predict trends.

Chapter 22 Vocabulary Terms half-life neutral nuclear reactions nucleons photosynthesis radiation radioactive radioactive isotope stable unstable alpha decay alpha particles beta decay beta particles carbon dating emissions fission fossil fuels fusion global warming

22.1 Nuclear Reactions In the Middle Ages, individuals called alchemists spent a lot of time trying to make gold. Making an element is possible only if you can achieve a nuclear reaction. Nuclear reactions involve either combining or splitting the nuclei of atoms.

22.1 Nuclear Reactions There are two kinds of nuclear reaction: fusion and fission. The process of combining the nuclei of atoms to make different atoms is called fusion.

22.1 Nuclear Reactions Breaking up the nucleus of an atom is called fission.

22.1 Nuclear Reactions Fission and fusion are nuclear reactions. Protons and neutrons—the two most important subatomic particles in the nucleus—participate in these reactions. Collectively, the protons and neutrons in the nucleus are called nucleons.

Comparing Chemical and Nuclear Reactions

22.1 Radioactivity An unstable nucleus is radioactive. Unstable isotopes emit three kinds of radioactive decay: — alpha particles — beta particles — gamma rays

Using Nuclear Reactions

22.1 Using Nuclear Reactions Radioactive isotopes can be used to detect problems in organ systems. The age of some fossils can be determined using radioisotopes such as carbon-14. It is possible to figure out the age of objects made from plants or animals that are between 50,000 and a few thousand years old using carbon dating.

22.1 Nuclear Reactions Key Question: How do you simulate nuclear decay? *Read text section 22.1 BEFORE Investigation 22.1

22.2 Carbon Reactions in the Environment We all depend on the carbon reactions performed by plants. Plants convert the sun’s energy into products we use.

22.2 Carbon Reactions in the Environment We depend on carbon reactions for transportation. Cars burn fossil fuels for energy. Use of fossil fuels affects the environment.

Incomplete combustion produces harmful by- products.

22.2 Carbon Reactions in the Environment Incomplete combustion means more air pollution. The catalytic converter, introduced in the 1970s, reduces hydrocarbon and carbon monoxide emissions by converting these molecules to carbon dioxide and water.

22.2 Carbon Reactions in the Environment Key Question: How do your choices impact the environment? *Read text section 22.2 BEFORE Investigation 22.2