NATSCI104 Inorganic Chemistry PDF

NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla MODUL...

NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla MODULE 2 MATTER AND ENERGY Brief Introduction or Description: This module intends to discuss matter and energy. These include principles of matter and energy, classification of matter, physical and chemical changes, and problem-solving involving energy, temperature, and heat capacity. Learning Outcomes: By the end of the module, you should be able to: 1. Explain the principles about matter and energy. 2. Classify matter according to their structures and properties. 3. Differentiate physical and chemical changes. 4. Solve problems involving energy, temperature and heat capacity. Lesson 1 Dalton’s Atomic Theory The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers, the scientists of their day. In the fifth century BC, Leucippus and Democritus argued that all matter was composed of small, finite particles that they called atomos, a term derived from the Greek word for “indivisible.” They thought of atoms as moving particles that differed in shape and size, and which could join together. Later, Aristotle and others came to the conclusion that matter consisted of various combinations of the four “elements”—fire, earth, air, and water—and could be infinitely divided. Interestingly, these philosophers thought about atoms and “elements” as philosophical concepts, but apparently never considered performing experiments to test their ideas. The Aristotelian view of the composition of matter held sway for over two thousand years, until English schoolteacher John Dalton helped to revolutionize chemistry with his hypothesis that the behavior of matter could be explained using an atomic theory. First published in 1807, many of Dalton’s hypotheses about the microscopic features of matter are still valid in modern atomic theory. Here are the postulates of Dalton’s atomic theory. 1. Matter is composed of exceedingly small particles called atoms. An atom is the smallest unit of an element that can participate in a chemical change. 2. An element consists of only one type of atom, which has a mass that is characteristic of the element and is the same for all atoms of that element. A macroscopic sample of an element contains an incredibly large number of atoms, all of which have identical chemical properties. Lesson 2 Matter Most of the Universe consists of matter and energy. Energy is the capacity to do work. Matter has mass and occupies space. All matter is composed of basic elements that cannot be broken down to substances with different chemical or physical properties. Elements are substances consisting of one type of atom, for example Carbon atoms make up diamond, and also graphite. Pure (24K) gold is composed of only one type of atom, gold atoms. Atoms are the smallest particle into which an element can be divided. The ancient Greek philosophers developed the concept of the atom, although they considered it the fundamental particle that could not be broken down. Since the work of Enrico Fermi and his colleagues, we now know that the atom is divisible, often releasing tremendous energies as in nuclear explosions or (in a controlled fashion in) thermonuclear power plants. Page 1 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Matter and Its Classification The three states of matter are the three distinct physical forms that matter can take in most environments: solid, liquid, and gas. In extreme environments, other states may be present, such as plasma, Bose Einstein condensates, and neutron stars. Further states, such as quark-gluon plasmas, are also believed to be possible. Much of the atomic matter of the universe is hot plasma in the form of rarefied interstellar medium and dense stars. Historically, the states of matter were distinguished based on qualitative differences in their bulk properties. Solid is the state in which matter maintains a fixed volume and shape; liquid is the state in which matter adapts to the shape of its container but varies only slightly in volume; and gas is the state in which matter expands to occupy the volume and shape of its container. Each of these three classical states of matter can transition directly into either of the other two classical states. Figure 1. States of Matter Figure 2. Classification of Matter Elements. A chemical element is a pure substance that consists of one type of atom. Each atom has an atomic number, which represents the number of protons that are in the nucleus of a single atom of that element. The periodic table of elements is ordered by ascending atomic number. The chemical elements are divided into the metals, the metalloids, and the non-metals. Page 2 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Metals, typically found on the left side of the periodic table, are: Often conductive to electricity malleable shiny and sometimes magnetic. Aluminum iron, copper, gold, mercury and lead are metals. In contrast, non-metals, found on the right side of the periodic table (to the right of the staircase), are: typically not conductive not malleable dull(not shiny) and not magnetic. Examples of elements that are non-metals include carbon and oxygen. Metalloids have some characteristics of metals and some characteristics of non-metals. Silicon and arsenic are metalloids. Compounds. A pure chemical compound is a chemical substance that is composed of a particular set of molecules or ions that are chemically bonded. Two or more elements combined into one substance through a chemical reaction, such as water, forma chemical compound. All compounds are substances, but not all substances are compounds. A chemical compound can be either atoms bonded together in molecules or crystals in which atoms, molecules or ions form a crystalline lattice. Compounds made primarily of carbon and hydrogen atoms are called organic compounds, and all others are called inorganic compounds. Compounds containing bonds between carbon and a metal are called organometallic compounds. Chemical compounds have a unique and defined structure, which consists of a fixed ratio of atoms held together in a defined spatial arrangement by chemical bonds. Chemical compounds can be: molecular compounds held together by covalent bonds salts held together by ionic bonds intermetallic compounds held together by metallic bonds complexes held together by coordinate covalent bonds. Pure chemical elements are not considered chemical compounds, even if they consist of diatomic or polyatomic molecules. Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it always has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride), and refined sugar(sucrose). Simple or seemingly pure substances found in nature can in fact be mixtures of chemical substances. For example, tap water may contain small amounts of dissolved sodium chloride and compounds containing iron, calcium, and many other chemical substances. Pure distilled water is a substance, but seawater, since it contains ions and complex molecules, is a mixture. Chemical Mixtures. A mixture is a material system made up of two or more different substances, which are mixed but not combined chemically. A mixture refers to the physical combination of two or more substances in which the identities of the individual substances are retained. Mixtures take the form of alloys, solutions, suspensions, and colloids. Page 3 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Heterogeneous Mixtures: a heterogeneous mixture is a mixture of two or more chemical substances (elements or compounds), where the different components can be visually distinguished and easily separated by physical means. Examples include: mixtures of sand and water mixtures of sand and iron filings a conglomerate rock water and oil a salad trail mix mixtures of gold powder and silver powder Homogenous Mixtures: a homogeneous mixture is a mixture of two or more chemical substances (elements or compounds), where the different components cannot be visually distinguished. Often separating the components of a homogeneous mixture is more challenging than separating the components of a heterogeneous mixture. Here are some homogeneous mixtures: Water itself is an example of a homogeneous mixture. It often contains dissolved minerals and gases, but these are dissolved throughout the water. Tap water and rainwater are both homogeneous, even though they may have different levels of dissolved minerals and gases. The air that you breathe is a homogeneous mixture of oxygen, nitrogen, argon, and carbon dioxide, along with other elements in smaller amounts. Because each layer of the Earth’s atmosphere has a different density, each layer of air is its own homogeneous mixture. An alloy is a metal comprised of two pure metals. Alloys such as steel and bronze are homogeneous mixtures of two metals. Chemical Solutions are usually homogeneous mixtures. The exception would be solutions that contain another phase of matter. For example, you can make a homogeneous solution of sugar and water, but if there are crystals in the solution, it becomes a heterogeneous mixture. All properties of matter are either physical or chemical properties and physical properties are either intensive or extensive. Extensive Properties such as mass and volume, depend on the amount of matter being measured. Intensive Properties such as density and color, do not depend on the amount of the substance present. Both extensive and intensive properties are physical properties, which means they can be measured without changing the substance's chemical identity. For example, the freezing point of a substance is a physical property: when water freezes, it's still water, it's just in a different physical state. Physical properties are properties that can be measured or observed without changing the chemical nature of the substance. Some examples of physical properties are: color (intensive) density(intensive) volume(extensive) mass(extensive) boiling point (intensive): the temperature at which a substance boils melting(intensive): the temperature at which a substance melts Page 4 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Chemical properties can be measured only by changing a substance's chemical identity. Here are several examples of chemical properties: Heat of combustion is the energy released when a compound undergoes complete combustion (burning) with oxygen. Chemical stability refers to whether a compound will react with water or air (chemically stable substances will not react). Hydrolysis and oxidation are two such reactions and are both chemical changes. Flammability refers to whether a compound will burn when exposed to flame. Again, burning is a chemical reaction commonly a high-temperature reaction in the presence of oxygen. There are two types of change in matter: physical change and chemical change. Physical change is a process that does not cause a substance to become a fundamentally different substance. Chemical change is a process that causes a substance to change into a new substance with a new chemical formula. Chemical changes are also known as chemical reactions. The "ingredients" of a reaction are called “reactants” and the end results are called products Lesson 3 Energy Physical and chemical changes are accompanied by energy changes. energy: the capacity to do work work: results from a force acting on a distance Types of Energy potential energy (PE): energy due to the position or composition of the object kinetic energy (KE): energy due to motion of the object An object’s total energy is the sum of its PE and KE Energy Conversions The Law of Conservation of Energy states that energy is neither created nor destroyed. Energy can change from one form to another or transferred from one object to another. Specific Types of Energy Electrical energy is the energy associated with the flow of electrical charge. Thermal energy is the energy associated with motions of particles of matter. Chemical energy is a form of PE associated with positions of particles in a chemical system. Energy Unit Conversions There are three common units for energy: Page 5 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Energy Diagram Chemical reactions can either be exothermic or endothermic. exothermic: release energy to surroundings Example: combustion endothermic: absorb energy from surroundings Example: photosynthesis Page 6 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Thermal Energy Atoms and molecules of matter are in constant, random motion, which is the source of thermal energy. More motion = more thermal energy. Temperature and Heat Temperature is the measure of the thermal energy of a substance. The hotter an object, the greater the motion of its particles, and the greater the thermal energy. Heat is the transfer or exchange of thermal energy caused by a temperature difference. Temperature Scales Page 7 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla Temperature Conversions Specific Heat Capacity Heat Capacity When you heat a substance, its temperature changes. The amount of change depends on the substance. heat capacity: quantity of heat needed to raise the temp of substance by 1 °C specific heat capacity: quantity of heat needed to raise temp of 1 g of substance by 1 °C. Energy and Heat Capacity Heat absorbed and temperature change are directly related as shown in the equation below. Page 8 of 9  NATSCI104: INORGANIC CHEMISTRY College of Liberal Arts, Sciences and Education Prepared by: Donh Arturo M. Tabernilla NAME: SCORE: COURSE AND SECTION: DATE: MODULE 2 MATTER AND ENERGY I. Classification and Properties of Matter Directions. Classify each of the following examples below as PURE SUBSTANCE or a MIXTURE. If the material is a pure substance, classify it as either ELEMENT or COMPOUND. If the material is a mixture, classify it as HOMOGENEOUS or HETEROGENEOUS. (1 pt. each) 1. Milk 2. Soil 3. Air 4. Chocolate Bar 5. Cologne 6. Hydrogen gas 7. Gold Nugget 8. Wine 9. Marshmallow 10. Table Salt II. Problem Solving on Temperature, Energy, and Heat Capacity Directions. Solve the following problems. Write an organized solution and box your final answer. A. Using the following food labels, solve the number of Joules for the given calories per serving. (5 pts. each) 2. B. Directions. Convert the following temperature to the given units. (3 pts. each) 1. 17.5 °C to °F 2. 178 K to °C 3. 147.76 °F to °C 4. 165.45 °C to K 5. 18917 °F to K C. Directions. Solve the following problems on heat capacity. Use the given table for specific heat capacity. 1. A 150-gram cube of lead is heated from 25 °C to 75 °C. How much energy was required to heat the lead? 2. A 55-gram metal is heated 300 °C with 3500 Joules of energy. What is the specific heat of the metal? Page 9 of 9