General Chemistry 2 CHEM 1214 Final Exam Preparation Guide Chapter 10 Interparticle Forces Liquids and Solids polarity presence of separation a lack of unity polar covalent bond asymmetric electron distribution in a covalent bond where a moderately high different 0 2 in electronegativity exists electronegativity EN tendency of an element to attract other electrons through polar covalent bonds bond type determined by difference in electronegativity EN EN is greater than 2 ionic bond EN is between 0 01 and 2 polar covalent bond EN is 0 non polar covalent bond the side with greater electronegativity has more electrons the side with lesser electronegativity has fewer electrons polarity is represented using a dipole arrow electronegativity is predictable on a Periodic table with the most electronegative elements being on the upper right hand corner of the table note polar bonds in a molecule does not dictate the polarity of a molecule this is determined a dipole arrow only how to determine polarity in a molecule draw a correct VSEPR structure identify the electronegative atoms draw the appropriate dipole arrow if the arrows are pointing in the same direction then the molecular is polar dipole moment the product of the change in magnitude Q in Coulombs and the distance between the atoms themselves d in meters molecules which are polar will display this property polar molecule Qd polar molecule non polar molecule intramolecular forces attractions which hold atoms together in a molecule ionic bonding between a cation and anion no electron sharing attraction is electronegative polar covalent bonding unequal sharing of electrons non polar covalent bonding equal sharing of electrons electronegativity is zero allow separate particles to congregate as molecules with similar properties will tend to stick together polarizability the ability to distort an electron cloud the electron cloud is comparable to clay and is moldable polarizability results in the development of a change in separation across a non polar particle intermolecular forces forces which hold molecules together ion dipole an ion charge and a dipole charge between an anion or cation and the pole of molecule with the opposite charge Cl and H2O or Na and H2O dipole dipole two dipoles charges between two oppositely charged particle poles of two separate polar molecules H bond a strong type of dipole dipole interaction a polar covalent bond between a hydrogen and a dipole charge of a negatively charged particle pole exclusively F O N particle General Chemistry 2 CHEM 1214 Final Exam Preparation Guide induced dipole between a cation or anion and an otherwise non polar molecule which has turned into a dipole through an electron cloud distortion ion induced dipole between a polar molecule and an otherwise non polar molecule which has turned into a dipole through an electron cloud distortion dispersion forces London results from an electron cloud distortion in a particle which forms polarization between two otherwise non polar molecules all matter possesses this force regardless of charge or polarity dispersion forces increase when molar mass and electron cloud size increases most powerful force ion dipole H bonding dipole dipole ion induced dipole induced dipole dispersion forces least powerful force such as salts and polar molecules non polar solvents dissolve solutes which lack a charged character non polar molecules physical properties vapor pressure boiling freezing point surface tension viscosity the stronger an intermolecular force the lower the vapor pressure the higher the boiling point the higher the surface tension and the higher the viscosity vapor pressure pressure of a liquid in equilibrium with its vapor intermolecular forces directly influence vapor pressure since more escape energy is required to liberate vapor from the liquid phase with strong intermolecular forces present dynamic equilibrium occurs when the rate of vaporization equals the rate of condensation where a constant temperature is established solubility polar solvents which have large polar charges can dissolve solutes with charge character like dissolves like similar solutes will dissolve in similar solvents viscosity resistance to flow in a liquid more viscous liquids will flow with less facility surface tension energy required to increase the surface area by a given amount capillarity a liquid s ability to climb up a thin tube only when adhesive forces are stronger than cohesive forces will a liquid climb up a tube physical changes condensation vaporization fusion melting freezing deposition sublimation heat flow occurs during physical changes highest temperature to lowest temperature gas liquid solid temperature changes can occur within a phase but NOT during a transition from one phase to another for example the transition from solid to liquid in H2O will ALWAYS be at 0 C this occurs because energy will be completely dedicated to breaking intermolecular bonds and cannot enter the surroundings cohesive forces attractive forces between molecules adhesive forces attractive forces between a molecule and a surface of a tube for example phase diagrams gas prefers high temperature and low pressure solid prefers low temperature and high pressure liquid prefers an intermediary between the two triple point where all three phases exist in equilibrium critical point where liquid and vapor are indistinguishable supercritical point phase present beyond critical point H2O has a solid state less dense than its liquid state which generates a negative slope in the diagram General Chemistry 2 CHEM 1214 Final Exam Preparation Guide Chapter 11 Colligative Properties of Solutions in a solution there is a solute dissolved material and what is being diluted and a solvent medium into which the solute is dissolved the environment mixture a combination of two ore more pure substances heterogenous mixtures not uniformly mixed homogenous mixtures uniformly mixed also known as a solution colloid a mixture where the solute is evenly dispersed in a solvent like medium Tyndall effect the scattering effect of light by particles in a colloid since the diameters of solute Brownian movement the random particle movement that colloid particles will display when they shift and disperse within the solvent particles and the wavelength of visible light are similar the solute is 1 1000 nm in size gels smoke foam a solution is the most homogenous with colloids slightly less so and suspensions the