Answer the following question given this paragraph: Explain why the fission of heavy nuclei releases energy. Similarly, why is it that energy input is required to fission light nuclei? 19. Explain, in terms of conservation of momentum and energy, why collisions of neutrons with protons will thermalize neutrons better than collisions with oxygen. The ruins of the Chernobyl reactor are enclosed in a huge concrete structure built around it after the accident. Some rain penetrates the building in winter, and radioactivity from the building increases. What does this imply is happening inside? 21. Since the uranium or plutonium nucleus fissions into several fission fragments whose mass distribution covers a wide range of pieces, would you expect more residual radioactivity from fission than fusion? Explain. The core of a nuclear reactor generates a large amount of thermal energy from the decay of fission products, even when the power-producing fission chain reaction is turned off. Would this residual heat be greatest after the reactor has run for a long time or short time? What if the reactor has been shut down for months? 23. How can a nuclear reactor contain many critical masses and not go supercritical? What methods are used to control the fission in the reactor? 24. Why can heavy nuclei with odd numbers of neutrons be induced to fission with thermal neutrons, whereas those with even numbers of neutrons require more energy input to induce fission? 25. Why is a conventional fission nuclear reactor not able to explode as a bomb?. Q: The core of a nuclear reactor generates a large amount of what type of energy from the decay of fission products, even when the power-producing fission chain reaction is turned off? Choices: - evaporation - elastic - erosion - thermal A:
thermal
(Question)
Answer the following question given this paragraph: As you know, density is defined as the mass per unit volume of a substance. Since gases all occupy the same volume on a per mole basis, the density of a particular gas is dependent on its molar mass. A gas with a small molar mass will have a lower density than a gas with a large molar mass. Gas densities are typically reported in g/L. Gas density can be calculated from molar mass and molar volume. Q: What is defined as the mass per unit volume of a substance? Choices: - weight - diameter - height - density A:
(Answer)
density
Ques: Answer the following question given this paragraph: In food chemistry, the substances known as antioxidants are reducing agents. Ascorbic acid (vitamin C; C6H8O6) is thought to retard potentially damaging oxidation of living cells. In the process, it is oxidized to dehydroascorbic acid (C6H6O6). In the stomach, ascorbic acid reduces the nitrite ion (NO2) to nitric oxide (NO): C6H8O6 + 2H+ + 2NO2 C6H6O6 + 2H2O + 2NO If this reaction did not occur, nitrite ions from foods would oxidize the iron in hemoglobin, destroying its ability to carry oxygen. Tocopherol (vitamin E) is also an antioxidant. In the body, vitamin E is thought to act by scavenging harmful by-products of metabolism, such as the highly reactive molecular fragments called free radicals. In foods, vitamin E acts to prevent fats from being oxidized and thus becoming rancid. Vitamin C is also a good antioxidant. Finally, and of greatest importance, green plants carry out the redox reaction that makes possible almost all life on Earth. They do this through a process calledphotosynthesis, in which carbon dioxide and water are converted to glucose (C6H12O6). The synthesis of glucose requires a variety of proteins called enzymes and a green pigment called chlorophyll that converts sunlight into chemical energy (Figure 5.7 "Life on Earth"). The overall change that occurs is as follows:. Q: Photosynthesis converts carbon dioxide and water into what? Choices: - insulin - carbon - glutamate - glucose A:
Ans: glucose
(Q).
Answer the following question given this paragraph: Chemistry in Everyday Life CERN Particle Accelerator Located near Geneva, the CERN ("Conseil Europeen pour la Recherche Nucleaire," or European Council for Nuclear Research) Laboratory is the world's premier center for the investigations of the fundamental particles that make up matter. It contains the 27-kilometer (17 mile) long, circular Large Hadron Collider (LHC), the largest particle accelerator in the world (Figure 21.13). In the LHC, particles are boosted to high energies and are then made to collide with each other or with stationary targets at nearly the speed of light. Superconducting electromagnets are used to produce a strong magnetic field that guides the particles around the ring. Specialized, purpose-built detectors observe and record the results of these collisions, which are then analyzed by CERN scientists using powerful computers. Q: The large hadron collider is the biggest type of what invention, which boosts particles to high energies? Choices: - electron microscope - mass spectrometer - nuclear reactor - particle accelerator A:
(A).
particle accelerator
Ques:Answer the following question given this paragraph: The scientist must next form a conclusion. The scientist must study all of the data. What statement best explains the data? Did the experiment prove the hypothesis? Sometimes an experiment shows that a hypothesis is correct. Other times the data disproves the hypothesis. Sometimes it's not possible to tell. If there is no conclusion, the scientist may test the hypothesis again. This time he will use some different experiments. No matter what the experiment shows the scientist has learned something. Even a disproved hypothesis can lead to new questions. Q: If no conclusion is reached after an experiment, the scientist may retest what? Choices: - conclusion - materials - suggestions - hypothesis A:

Ans:hypothesis
Answer the following question given this paragraph: The radiation exposure is determined by the number of rads times the quality factor of the radiation. Q: The radiation exposure is determined by the number of what times the quality factor of the radiation? Choices: - pounds - units - beacons - rads A:
rads