I.-CHEMISTRY-The-Study-of-Change.pdf

Miguel Angelito T. Lacasan Why Study Chemistry?  Learning Outcomes 1.1 Describe the scope of chemistry, its concerns and its many fields 1.2 Define some terms associated with chemistry, matter, and energy 1.3 Identify the classification or form of matter based...

Miguel Angelito T. Lacasan Why Study Chemistry?  Learning Outcomes 1.1 Describe the scope of chemistry, its concerns and its many fields 1.2 Define some terms associated with chemistry, matter, and energy 1.3 Identify the classification or form of matter based on its composition and the types of energy 1.4 Describe some classification and separation techniques 1.5 Differentiate the changes and properties of matter and their various states  Chapter 1 Some Fundamental Definitions  Chemistry Chemistry is the study of matter, its properties, the changes that matter undergoes, and the energy associated with these changes.  Definitions anything that has both mass and volume Matter - the “stuff” of the universe: books, planets, trees, professors, students Composition the types and amounts of simpler substances that make up a sample of matter Properties the characteristics that give each substance a unique identity  Energy in Chemistry Energy is the ability to do work. Work is the action of a force through a distance F = m. a = N = kg.m/s2 W = F. d = J = N.m  Energy Changes Potential Energy PE = mgh = J is energy due to the position of an object. Kinetic Energy is energy due to the movement of an object. KE = 1/2mv2 = J  Energy Changes Lower energy states are more stable and are favored over higher energy states. Energy is neither created nor destroyed – it is conserved – and can be converted from one form to another.  Potential energy is converted to kinetic energy. A gravitational system. The potential energy gained when a lifted weight is converted to kinetic energy as the weight falls. A lower energy state is more stable.  Potential energy is converted to kinetic energy. A system of fuel and exhaust. A fuel is higher in chemical potential energy than the exhaust. As the fuel burns, some of its potential energy is converted to the kinetic energy of the moving car.  Chapter 2 The States of Matter The States of Matter  The States of Matter Solid Liquid Gas  The States of Matter Endothermic Process Exothermic Process The States of Matter Interconversion of the Three States  The States of Matter Plasma is a lot like a gas, but the particles are electrically charged.  Chapter 3 Classification of Matter Classification of Matter  Definitions for Components of Matter Element - the simplest type of substance with unique physical and chemical properties. An element consists of only one type of atom. It cannot be broken down into any simpler substances by physical or chemical means. Molecule - a structure that consists of two or more atoms that are chemically bound together and thus behaves as an independent unit.  Definitions for Components of Matter Compound - a substance composed of two or more elements which are chemically combined. Mixture - a group of two or more elements and/or compounds that are physically intermingled.  Examples of Elements Table 1.1 Some Common Elements and Their Symbols. The chemistry of cellular phones.  Compounds A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. Compounds can only be separated into their pure components (elements) by chemical means. Table 1.2 Some Properties of Sodium, Chlorine, and Sodium Chloride. Property Sodium + Chlorine Sodium Chloride Melting point 97.8°C -101°C 801°C Boiling point 881.4°C -34°C 1413°C Color Silvery Yellow-green Colorless (white) Density 0.97 g/cm3 0.0032 g/cm3 2.16 g/cm3 Behavior in water Reacts Dissolves slightly Dissolves freely  Types of Mixtures A mixture is a combination of two or more substances in which the substances retain their distinct identities. Homogenous mixture (solution) Heterogeneous The composition of the mixture mixture is the same The composition is throughout (at the not uniform atomic/molecular level). throughout. Homogeneous Heterogeneous  Types of Mixtures Heterogeneous Mixture Homogeneous Mixture  Types of Homogeneous Mixtures 1. Solutions ✓ composed of two or more components which can be separated by physical means. ✓ Have uniform properties all throughout, single phase ✓ Examples: coffee, 70% rubbing alcohol, alloys like brass & steel, vinegar.  Types of Heterogeneous Mixtures 1. Colloids ✓ Appear homogeneous through the naked eye but heterogeneous through the microscope. ✓ They are not affected by gravity and do not settle at the bottom of a container. ✓ Exhibit Tyndall effect (scattering of a beam of light by colloidal particles). ✓ Examples: Fog and clouds (liquid particles in a gas), milk (solid particles in a liquid), and butter (solid particles in a solid),  Types of Heterogeneous Mixtures 2. Suspension - particles are greater than colloidal particles and settle at the bottom of the container. Examples: antibiotic suspension, muddy water, milk of magnesia, slaked lime for whitewashing, and aerosol. 3. Coarse – Particles are greater than that of suspension. Ex: Fruit salad, gravel, pizza  The distinction between mixtures and compounds. S2- Fe2+ A physical mixture of Fe and S8 can be Fe and S have reacted chemically to separated using a magnet. form the compound FeS. The elements cannot be separated by physical means.  Basic Separation Techniques Filtration: Separates components of a mixture based upon differences in particle size. Filtration usually involves separating a precipitate from solution. Crystallization: Separation is based upon differences in solubility of components in a mixture. Distillation: separation is based upon differences in volatility. Extraction: Separation is based upon differences in solubility in different solvents (major material). Chromatography: Separation is based upon differences in solubility in a solvent versus a stationary phase. The Distillation Set-up Principle of Gas-Liquid Chromatography (GLC)  Chapter 4 Properties of Matter  According to the change According to dependence involved during measurement on amount of matter of the property Physical Chemical Extensive Intensive Properties Properties Properties Properties  Physical and Chemical Properties Physical Properties properties a substance shows by itself without interacting with another substance - color, melting point, boiling point, density Chemical Properties properties a substance shows as it interacts with, or transforms into, other substances - flammability, corrosiveness, toxicity, reactivity  Physical Properties 1. Color – how the object absorbs and 2. Texture – how the substance looks and reflects light feels.  Physical Properties 3. Temperature 4. Mass A measure of the average kinetic energy The amount of matter in an object (energy of motion) of particles in a (in g or kg). substance.  Physical Properties 5. Volume 6. Density The amount of space an object occupies (in the ratio of mass to volume; reflects the degree of mL, L, cm3, m3, etc.) packing of particles in matter. mass Density = volume  Physical Properties 7. Luster 8. Ductility The way that a substance reflects light Ability of a substance to be (metallic, non-metallic, glassy, pearly, dull). stretched into a wire.  Physical Properties 9. Malleability 10. State Ability of a substance to be hammered flat and (phase) of matter to retain the new shape. Table 1.1 Some Characteristic Properties of Copper  Extensive and Intensive Properties An extensive property of a material depends upon how much matter is being considered. An intensive property of a material does not depend upon how much matter is being considered.  Extensive Properties An extensive property depends only on the number of particles, not on their composition or internal arrangement. (extensive ~ external)  Intensive Properties An intensive property are determined by the chemical composition of the particles and their structure (arrangement). (intensive ~ internal)  Chapter 5 Changes of Matter  Physical and Chemical Changes A physical change does not A chemical change alters alter the composition or the composition or identity of a substance. identity of the substance(s) involved. The Distinction Between Physical and Chemical Change. Physical Changes Chemical Changes  YouYou are living You occupy space and has mass MATTER!