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What does the term discrediting mean?

When fat comes in contact with sodium hydroxide, it produces soap and glycerin. determine whether this is a physical change or a chemical change. explain your answer

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.