Please answer this: I read this background article the other day: An anaerobic organism is any organism that does not need oxygen for growth and even dies in its presence. Obligate anaerobes will die when exposed to atmospheric levels of oxygen. Clostridium perfringens bacteria, which are commonly found in soil around the world, are obligate anaerobes. Infection of a wound by C. perfringens bacteria causes the disease gas gangrene. Obligate anaerobes use molecules other than oxygen as terminal electron acceptors.  I am facing a new situation today: Microbiologist John is studying the anaerobic organism. He collected two samples of this organism, sample A and sample B. Sample A is an anaerobic organism, and sample B is specifically identified as the Clostridium perfringens obligate anaerobe. To compare these samples to other organisms he collected another microbe that is not an anaerobic organism. He labeled it as sample C.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which sample would cause gas gangrene, sample B or sample C?
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Answer: sample B


Please answer this: I read this background article the other day: If only 1.0 mL of 0.10 M hydrochloric acid is added to 1.0 L of pure water the pH drops drastically from 7.0 to 4.0. This is a 1000-fold increase in the acidity of the solution. For many purposes, it is desirable to have a solution which is capable of resisting such large changes in pH when relatively small amounts of acid or base are added to them. Such a solution is called a buffer. A buffer is a solution of a weak acid or a base and its salt. Both components must be present for the system to act as a buffer to resist changes in pH. Commercial buffer solutions, which have a wide variety of pH values, can be obtained.  I am facing a new situation today: John is a scientist in a large pharmaceutical company. He devices many useful products using his knowledge of chemistry. Today, he has four solutions in front of him, solution A, solution B, solution C, and solution D. Solution A is a buffer, but solution B is not a buffer. Solution C is acidic, but solution D is not acidic. He needs to figure out what each solution does.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Would solution C increase or decrease the pH of pure water?
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Answer: decrease


Please answer this: I read this background article the other day: The general trend in electronegativity is that the value increases from left to right across a row in the periodic table and decreases down a column. The most electronegative element is fluorine, which has a value of 4.0. As discussed in the lesson "Trends in the Periodic Table," electronegativity increases across a row as the number of protons in the nucleus increases and therefore has a stronger pull. Electronegativity decreases down a column due to an increased effect of electron shielding in larger atoms.  I am facing a new situation today: A high school student, Timmy, is reading about elements of a periodic table. He is studying the periodic table when he decides to compare two random elements within the same column. He chooses Mardine and Sampline to compare and contrast and gets to work. The first thing he notices is that Sampline is further down the periodic table than Mardine. It's not much information to go on, but it's a good starting point for Timmy.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Is electron shielding higher or lower in Mardine?
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Answer:
lower