Properties of Liquids and Solids - Chemistry Presentation

e s o f l i q u i d s Prop er t i and th e I M F Ch emis try 2 Genearl  WHAT ARE INTERMOLECULAR FORCES? the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between atoms and other types of nei...

e s o f l i q u i d s Prop er t i and th e I M F Ch emis try 2 Genearl  WHAT ARE INTERMOLECULAR FORCES? the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between atoms and other types of neighboring particles Affects how particles interact with one another (whether they want to be close together, or far apart) Stronger forces = more energy to overcome  KINETIC ENERGY When liquid particles gain When liquid particles lose enough kinetic energy to energy so that the overcome their intermolecular intermolecular forces become attractions, the liquid strong enough to hold the becomes a gas. particles in fixed positions, the liquid becomes a solid.  How do intermolecular forces and kinetic energy affect the movement of particles in a liquid?  PARTICLES IN LIQUIDS Kinetic energy of liquid particles is based on the intermolecular attraction of the particles in the liquid PARTICLES NOT FIXED IN PLACE, THEY ARE ABLE TO MOVE AROUND EACH OTHER ABLE TO FLOW AND TAKE SHAPE OF CONTAINER DENSER THAN GASES, PARTICLES ARE CLOSER TOGETHER FIXED VOLUME (NOT COMPRESSIBLE) EXAMPLES: WATER AT ROOM TEMPERATURE, MERCURY, ALCOHOL  Surface Tension -the tendency for a liquid surface to resist penetration Directly correlated to intermolecular attraction Surfactant can reduce surface tension  Structure and Properties of Water Liquids that have strong intermolecular forces also have a high surface tension  Cohesive and Adhesive Forces Cohesive Forces (Mercury) Between the molecules in the liquid Adhesive Forces (Water) Between the molecules and the surface of another substance  Viscosity The measure of a liquid’s resistance to flowing Viscosity = Speed related to the intermolecular forces present Viscosity = stronger IMF = temperature  Vapor Pressure Open : Some water molecules go out Closed: none of the gas particles are able to go out  Equilibrium Vapor Pressure HIGH HEAT VAPORIZATION. Pressure exerted by the gas in equilibrium with a liquid in a closed container at a given temperature The molecules in the gaseous state over its liquid create a pressure. Number of gaseous particles Pressure What happens at a liquid's boiling point?  What is Boiling? Boiling is the rapid phase change of a liquid becoming a gas. During boiling, bubbles rise to the surface of liquid because they are less dense than the surrounding liquid. Boiling happens when the vapor inside of the bubbles of a liquid has high enough kinetic energy to continuously push outward until the bubble reaches the surface of the liquid. Boiling Point The boiling point is when the vapor pressure is strong enough to overcome the pressure of the surroundings (atmospheric pressure) It is a specific property of a liquid, so different substances have different boiling points.  Structure and Properties of Water The high boiling point of water is a consequence of its strong intermolecular forces of attraction caused by the formation of the H-bond. It also explains why water is liquid at room temperature.  Structure and Properties of Water HIGH SPECIFIC HEAT. Specific heat refers to the amount of heat needed to change the temperature of 1 gram of a substance by 1⁰C. For water, its specific heat is 1cal/g⁰C. It means that water can absorb and release large quantities of heat without change in temperature. This is the reason why body temperature remains at 37⁰C even when there is a change in the surroundings.  Structure and Properties of Water HIGH DENSITY IN ITS LIQUID FORM Density is the mass of a substance per unit volume, typically expressed as grams per cubic centimeter (g/cm³) or kilograms per liter (kg/L).  Intermolecular Forces and Physical Properties Intermolecular forces Boiling point Vapor Pressure Viscosity Surface tension Density  Types and Properties of Solid CRYSTALLINE SOLIDS AND AMORPHOUS SOLIDS The representative particles in crystalline solids exist in a highly ordered and repetitive pattern. This orderly arrangement produces a beautiful regularly shaped crystal. NaCl and sugar are crystalline in form and so is snow. Many precious stones used in jewelry are crystals. The definite patterns that repeat themselves in solid crystals are called unit cells. AMORPHOUS SOLIDS CRYSTALLINE SOLIDS  ARRANGEMENT OF PARTICLES THE COMPONENTS OF A SOLID CAN BE ARRANGED IN TWO GENERAL CRYSTALLINE SOLIDS WAYS: AMORPHOUS SOLIDS they can form a regular repeating they can aggregate with no particular three-dimensional structure called a long range order, and form an crystal lattice, thus producing a amorphous solid (from the Greek crystalline solid’ ámorphos, meaning “shapeless”).  ARRANGEMENT OF PARTICLES THE COMPONENTS OF A SOLID CAN BE ARRANGED IN TWO GENERAL WAYS: Crystalline solids are arranged in fixed geometric patterns or lattices. Examples of crystalline solids are ice and sodium chloride (nacl), copper sulfate (cuso4), diamond, graphite, and sugar (c12h22o11). The ordered arrangement of their units maximizes the space they occupy and are essentially incompressible.  ARRANGEMENT OF PARTICLES THE COMPONENTS OF A SOLID CAN BE ARRANGED IN TWO GENERAL WAYS: AMORPHOUS SOLIDS have a random orientation of particles. Examples of amorphous solids are glass, plastic, coal, and rubber. they are considered super-cooled liquids where molecules are arranged in a random manner similar to the liquid state.  TYPES OF CRYSTALS IONIC SOLIDS The particles of ionic solids are positive and negative ions. Since oppositely charged particles are present, the forces between the ions are electrostatic in nature. The Crystal arrangement in 1onic solids maximizes attractions and simultaneously minimizes repulsion making the compound possess a high degree of stability.  TYPES OF CRYSTALS COVALENT SOLIDS This type of solids is made up of atoms and are joined by covalent bonds. Some solids form covalent bonds resulting in the formation of molecules. In some solids, however, molecules are not formed. Rather, a covalent network is formed extending throughout the solid crystal.  TYPES OF CRYSTALS METALLIC SOLIDS A metallic solid is a type of solid where the atoms are held together by metallic bonds, which are a special kind of bond formed between metal atoms. In these solids, valence electrons (the outermost electrons) are not bound to individual atoms but instead form a "sea of electrons" that move freely throughout the solid.  TYPES OF CRYSTALS MOLECULAR SOLIDS The particles in molecular solids can either be atoms or molecules held together by intermolecular forces like dispersion forces, dipole-dipole forces, and hydrogen bonds as discussed in this section. They are poor conductors of heat and electricity because there are no free moving electrons and no charged particles.