I read this background article the other day: For example, if a solid pellet of NaOH is placed into a chamber of HCl gas, a relatively slow acid-base reaction will occur between gaseous HCl molecules and hydroxide ions on the surface of the pellet. If we were to grind the pellet into smaller pieces, it would greatly increase the total surface area, and therefore the overall reaction rate. Once ground up, many hydroxide ions that were on the interior of the pellet, where they were not exposed to any HCl molecules, will now be on the surface, where the necessary collisions can occur. I am facing a new situation today: In his chemistry lab David is experimenting with how NaOH and HCl gas reacts with each other. He conducted two experiments, experiment A and experiment B. In experiment A he used solid pellets of NaOH, but in experiment B he used ground NaOH. He was surprised to see the difference it made in his experiment. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Would experiment A's hydroxide have smaller or larger surface area than experiment B's hydroxide?
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Answer: smaller

I read this background article the other day: Hepatitis B is a disease of the liver. It is caused by a virus called hepatitis B, which can be passed through sexual activity. Hepatitis B causes vomiting. It also causes yellowing of the skin and eyes. The disease goes away on its own in some people. Other people are sick for the rest of their lives. In these people, the virus usually damages the liver. It may also lead to liver cancer. Medicines can help prevent liver damage in these people. There is also a vaccine to protect against hepatitis B. I am facing a new situation today: Two identical twin brothers go to the doctor to get blood work done and also checked for STDs as part of their routine medical checkups. Neither man thinks they have caught anything, but both are sexually active so they want to get checked out. After getting the test results, the doctor tells Hank that he has strep throat, but no STDs. Jacob is told that he has hepatitis B. The doctor gives both men information about what medication to take and what they need to do to manage their diseases. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which man is less likely to have gotten a hepatitis B vaccine?
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Answer: Jacob

I read this background article the other day: As a young man, Bohr worked in Rutherford's lab in England. Because Rutherford's model was weak on the position of the electrons, Bohr focused on them. He hypothesized that electrons can move around the nucleus only at fixed distances from the nucleus based on the amount of energy they have. He called these fixed distances energy levels, or electron shells. He thought of them as concentric spheres, with the nucleus at the center of each sphere. In other words, the shells consisted of sphere within sphere within sphere. Furthermore, electrons with less energy would be found at lower energy levels, closer to the nucleus. Those with more energy would be found at higher energy levels, farther from the nucleus. Bohr also hypothesized that if an electron absorbed just the right amount of energy, it would jump to the next higher energy level. Conversely, if it lost the same amount of energy, it would jump back to its original energy level. However, an electron could never exist in between two energy levels. These ideas are illustrated in the Figure below . I am facing a new situation today: Greg was studying Bohr's model. He found it helpful to categorize different scenarios in the model. First, he labeled electron with higher energy as cat A, and electron with lower energy as cat B. Then he labeled electron that gained energy as cat C, and election that lost energy as cat D. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which electron would be farther from the nucleus, cat A or cat B?
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Answer:
cat A