[Q]: 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 A resist or assist in changes in pH?
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[A]: resist

[Q]: I read this background article the other day: In grassland, much of the organic matter added to the soil is from the deep, fibrous, grass root systems. By contrast, tree leaves falling on the forest floor are the principal source of soil organic matter in the forest. Another difference is the frequent occurrence in the grasslands of fires that destroy large amounts of aboveground material but stimulate even greater contributions from roots. Also, the much greater acidity under any forests inhibits the action of certain soil organisms that otherwise would mix much of the surface litter into the mineral soil. As a result, the soils under grasslands generally develop a thicker A horizon with a deeper distribution of organic matter than in comparable soils under forests, which characteristically store most of their organic matter in the forest floor (O horizon) and thin A horizon. I am facing a new situation today: Kim and Jane inherited some land. Kim inherited some grassland, while Jane inherited a forest. They both took good care of their properties. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which person inherited a parcel with a thinner A horizon?
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[A]: Jane

[Q]: I read this background article the other day: Hydrogen bonds cause water to have a relatively high boiling point of 100C (212F). Because of its high boiling point, most water on Earth is in a liquid state rather than in a gaseous state. Water in its liquid state is needed by all living things. Hydrogen bonds also cause water to expand when it freezes. This, in turn, causes ice to have a lower density (mass/volume) than liquid water. The lower density of ice means that it floats on water. For example, in cold climates, ice floats on top of the water in lakes. This allows lake animals such as fish to survive the winter by staying in the water under the ice. I am facing a new situation today: Scientists are finding more and more evidences of water in the outer space. Earth has mostly liquid water. But that's not the case with other celestial objects. Venus has some water, but it is in gaseous state. On the other hand, water in Jupiter's moon Europa is in frozen state. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: In which place the state of water is in higher density, Earth or Europa?
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[A]: Earth

[Q]: I read this background article the other day: Saturated hydrocarbons are given the general name of alkanes . The name of specific alkanes always ends in - ane . The first part of the name indicates how many carbon atoms each molecule of the alkane has. The smallest alkane is methane. It has just one carbon atom. The next largest is ethane, with two carbon atoms. The chemical formulas and properties of methane, ethane, and several other alkanes are listed in Table below . The boiling and melting points of alkanes are determined mainly by the number of carbon atoms they have. Alkanes with more carbon atoms generally have higher boiling and melting points. I am facing a new situation today: Two brothers studied chemistry in school. Ted studied alkanes, while Ned studied cycloalkanes. They both received grade A. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which brother learned less about the boiling points of alkanes?
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[A]:
Ned