Chem 104 1st Edition Lecture 10 Outline of Last Lecture I. Vapor Pressure vs. temperatureII. Boiling PointIII. Supercritical FluidA. The critical temperature and the critical pressureIV. Stages of solid, gas, and liquidA. Sublimation and depositionB. The different stages and their importanceV. HeatA. Heat of fusion and its process to solve for itB. The heat curve of water and its segment processOutline of Current Lecture I. Phase diagrams and their purposeII. Solids and their properties and structuresA. Unit cells: the basicsIII. Solutions and solubilityCurrent LectureI. Phase diagrams describe different states and the state changes that occur. As freezing point increases the pressure increases. The lines represent state changes. The triple point is when the states of liquid, gas, and solid coexist.II. Solids will form a crystal lattice with their particles when allowed to cool slowly because they arrange themselves in a formation to give themselves their maximum attractive forces. The smallest unit that shows the pattern for all the particles is the unit cell. Unit cells are 3D and repeated over and over to give a crystalline structure. Each particle in the unit cell is called a lattice point. Lattice planes are planes connecting points in the unit cells throughout the lattice.a. There are 7 unit cells:i. Cubicii. Tetragonaliii. Orthorhombiciv. Monoclinicv. Hexagonalvi. Rhombohedralvii. Triclinicb. Cubic Unit Cells have equivalent sides (a=b=c), all with a 90° angle.c. Tetragonal unit cells sides are not all equivalent. The ratio is a=c<b. Once again all the angles equal 90°.III. The coordination number of unit cells is the number of other particles each particle is in contact with. Thus, the higher the coordination number, the more interactions there will be among particles,therefore the stronger the attractive forces. The overall packing efficiency is the percentage of volume in the unit cell occupied by the particles. Also, the higher the coordination number, the moreefficient the packing of particles.a. Cubic cells can be made of spherical particles. A 1/8 of each particle make up the corners, ½ of each particle is on the face within the cube, and ¼ of each particle is on an edge within the cube. Simple cubic is the eight particles that make up each corner of a cube. So the math is shone as 8 corners * 1/8. Face cubic center is the same as center of face. The particles are only shared by the face adjacent to it so its math equal is 6 faces *½. IV. Solutions are comprised of a solute and solvent, this is the breaking of bonds to create new bonds. The solute is the component that changes state. The solvent is the component that keeps its state. Solutions can be different types of mixtures, one being homogeneous; when multiple materials are contained in one mixture and seem to disappear, giving the solution a consistent appearance throughout.a. Solubility is when one substance dissolves in another. When one substance doesn’t dissolve in another it is insoluble. Spontaneous mixing is when solutions with different solute concentrations come in contact; they spontaneously mix to result in a uniform distribution. Remember: solvent-solute bonds must be stronger in order to make the solution and break from their original
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