Study Guide Exam II - Lecture 11: Food Chemistry: The...

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Lecture 11: Food Chemistry: The Basics 1. define the terms: functionality (as applied to food systems), elements, compounds (or molecules), mixtures, isotopes, triple point, critical point Functionality: the chemical and physical properties of macronutrients Elements: They are composed of one kind of atom. Atoms themselves are composed into subatomic particles (electrons, protons, and neutrons) Compounds: Composed of two or more elements. Simplest is binary compound. Mixtures: Composed of two or more compounds, but these compounds retain their discrete chemical identity. Isotopes: Elements that have a set number of protons and electrons, but different amount of neutrons. Triple point: Where the solid, liquid, and gas phases are in equilibrium Critical point: The beginning of the supercritical fluid region (a range of very high temperature and pressure values) 2. explain the 2 types of chemical bonds between elements (to form compounds) and the 3 types of intermolecular forces between compounds Chemical Bonds: compounds are held together by net electrical forces attraction Ionic Bond: attraction between opposite charges of cation and anion. Complete transfer of electrons from one element to another. Covalent Bonds: Sharing of electrons. Single, double, and triple bonds are possible Types of Intermolecular Forces: o London Forces: The interaction between transient instantaneous electric dipoles from neighboring molecules o Dipole-Dipole: Forces between two permanent electric dipoles; common to polar molecules o Hydrogen Bonds: consists of a hydrogen atom lying between two strongly electronegative atoms and covalently bonded to one of them (F, O, N) . the electronegative atom may be located on different molecules or in different regions of the same molecule 3. list and describe using relevant examples the 3 fundamental phases of matter and the 1 pseudo-phase
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Solid: Fixed volume and fixed shape Liquid: fixed volume, but not fixed shape Gas: no fixed volume or shape Pseudo-phase: shares the properties of two phases 4. identify the phases (or states) of matter in a given food system (e.g., a can of coke) To find out the states of matter in a given food system, look at the Phase Diagram. The lines do not represent the phases, instead they represent the transition phases. 5. discuss how the phase diagram works to predict the phase of matter and the phases transitions (i.e., solid to liquid) as a function of pressure and temperature The lines of the phase diagram represent the transitions. 6. use the phase diagram to describe the effect of temperature and pressure on molecule mobility If a horizontal line is present, this means that pressure is constant. As you increase the temperature, mobility increases. If a vertical line is present,
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This note was uploaded on 03/16/2011 for the course FSHN 101 taught by Professor Schmidt during the Spring '08 term at University of Illinois, Urbana Champaign.

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Study Guide Exam II - Lecture 11: Food Chemistry: The...

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