Chemistry for Engineers PRELIMINARY TERM PDF

Southern Luzon State University COLLEGE OF ENGINEERING BATCH 2027 Science, Technology and Society CHM01a - PRELIMINARY TERM 1 - GB | 1st SEMESTER | MS. RAIANNE JOY MAULION CHEMISTRY FOR ENGINEERS...

Southern Luzon State University COLLEGE OF ENGINEERING BATCH 2027 Science, Technology and Society CHM01a - PRELIMINARY TERM 1 - GB | 1st SEMESTER | MS. RAIANNE JOY MAULION CHEMISTRY FOR ENGINEERS divided, and then limit the significant figures in the answer to the lowest count. Ex. 10.273 (4 sf) ÷ 105.93 (5 sf) = COURSE OUTLINE 0.0969508 →reduce to 4sf only ~ 0.09695 I. Experimental Observation 5. For addition and subtraction, find the smallest A. Three Parts to Measurement. decimal place that all values have in common and are 1. The Numerical Value and the significant and that is the last significant decimal Significant Figures place in your answer. Add the values like normal 2. The Units of Measurement and the SI and round to the significant decimal place. Units Ex. 3. An estimate of the uncertainty of the measurement II. Thermochemistry A. Energy 1. Forms of Energy 2. Energy Units B. Energy Changes in Chemical Reaction SCIENTIFIC NOTATION C. Introduction to Thermodynamics D. Heat Capacity and Calorimetry a number, n, is shown as the product of that number 𝑥 REFERENCE and 10, raised to some exponent x; that is, (𝑛 × 10 ). Operationally, what you are doing is moving Modules in Chemistry for Engineers decimal places Lecture Notes ○ Ex. the number of copper atoms in a penny, 28,000,000,000,000,000,000,000 EXPERIMENTAL OBSERVATION To get the power of 10 that we need, we begin with the last digit in include the measurement of mass, length, volume, the number and count the number temperature, and time. of places that we must move to the left to reach our new decimal point. THREE PARTS TO MEASUREMENT we must move 22 places to the 1. Its numerical value left 2. The unit of measurement that denotes the scale and the number is written in 22 3. An estimate of the uncertainty of the measurement scientific notation as 2. 8 × 10. THE NUMERICAL VALUE AND SIGNIFICANT FIGURES THE UNITS OF MEASUREMENT AND SI UNITS The numerical value of a laboratory measurement in the Philippines, we had salop to measure the should always be recorded with the proper amount of rice and other grains for trading. number of significant figures. In 1960, an international committee met in France SIGNIFICANT FIGURES - meaningful digits in a to establish the International System of Units, a measured or calculated quantity revised metric system now accepted by scientists When significant figures are used, the last digit is throughout the world. understood to be uncertain. ○ this system is called SI units, from the French Système International d’Unités. GUIDELINES FOR SIGNIFICANT FIGURES: 1. Any digit that is not zero is significant. Thus, 432 cm has 3 significant figures (sf), 1.212 kg has 4 sf, and so on. 2. Zeros between nonzero digits are significant. Thus, 606 m contains 3 significant figures, 40,501 kg contains five significant figures, and so on 3. Zeros to the left of the first nonzero digit are not significant. Their purpose is to indicate the placement of the decimal point. Ex. 0.08 L contains one significant figure 0.0000349 g contains three significant Table 1.1. The SI base units figures 4. For multiplication and division, count the number of significant figures in each number being multiplied or  xo,navi. TEMPERATURE is a measure of how hot or cold a substance is relative to another substance. differs from heat, which is the energy that flows between objects that are at different temperatures. The SI base unit of temperature is the kelvin (K) THE THREE IMPORTANT TEMPERATURE SCALE: ○ Celsius - °C, formerly called centigrade ○ Kelvin - denoted by K ○ Farenheit - denoted by °F Table 1.2. Prefixes used with SI Units Figure 1.1 Conversion of Temperature Scales Table 1.3. Examples of SI-derived quantities MASS AND WEIGHT CONCEPT OF MOLE AND MOLAR MASS are different quantities Chemists are interested primarily in mass Mole (mol) - SI unit for amount of substance ○ Mass ○ Amount of substance - concerned with can be determined readily with a counting entities rather than measuring the balance; the process of measuring mass of a sample. 23 mass, oddly, is called weighing Avogadro’s Constant - 6. 02 × 10 SI unit for mass is kilogram. In specifies the number of objects in a fixed mass of chemistry, however, the smaller unit substance. gram (g) is more convenient. Molar Mass (M) - is the mass per mole of its entities (atoms, molecules, or formula units). Denoted by g/mol. Molar mass of an Element molar mass of an element is equal to its atomic mass. ○ Ex. the molar mass of Fe is 55.86 g/mol Molar mass of a Compound VOLUME is the sum of the atomic masses in the molecule. The SI unit of length is the meter (m) ○ Ex. 3 SI-derived unit for volume is the cubic meter (𝑚 ) Chemists work with much smaller volumes, such as 3 the cubic centimeter (𝑐𝑚 ) Another common unit of volume is the liter (L). ○ LITER - volume occupied by one cubic decimeter. One liter of volume is equal to 1000 milliliters (mL) or 1000 cm3 2 I Chemistry for Engineers - 1st SEMESTER  xo,navi. Interconverting Mass, Mole, and Number FORMULA: of Chemical Entities Figure 1.2 The relationships between mass (m in grams) of an EXAMPLE: element and number of moles of an element (n) and between number of moles of an element and number of atoms (N) of an element. M is the molar mass (g/mol) of the element and NA is Avogadro’s number Molality Given by: CONCENTRATION UNITS Solution - a homogeneous mixture of two or more 𝑚𝑜𝑙 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 substances. ○ Solute - minor species in solution 𝑚= 𝑘𝑔 𝑜𝑓 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 ○ Solvent - major species in solution, which most of the time is WATER PERCENT CONCENTRATION Concentration - states how much solute is contained Weight Percent - used to express the concentration in a given volume or mass of solution or solvent of commercial aqueous reagents. Molarity Volume Percent - commonly used to specify the most commonly used units in chemistry concentration of a solution prepared by diluting a pure Molarity (M) - also known as molar concentration, is liquid compound with another liquid. the number of moles of solute per liter of solution. 3 I Chemistry for Engineers - 1st SEMESTER  xo,navi. FORMULA: FORMULA: EXAMPLE: EXAMPLE: Preparation of Solution and Dilution Distillation - water is boiled to separate it from less volatile impurities and the vapor is condensed to liquid that is collected in a clean container Figure 1.3 Distillation Parts per Million and Parts per Billion Deionization - water is passed through a column that removes ionic impurities. Nonionic impurities dilutes solution can be expressed as parts per million remain in the water. (ppm) or parts per billion (ppb). PPM or PPB - means grams of solute per million or billion grams of total solution or mixture if the volume of solution is given, then it must be in milligrams (mg) 4 I Chemistry for Engineers - 1st SEMESTER  xo,navi. MEASUREMENT UNCERTAINTY Accuracy how "correct" a measured or calculated value is, that is, how close the measured value is to an actual or accepted value. Precision describes the closeness of several measurements to each other. THERMOCHEMISTRY ENERGY ENERGY usually defined as the capacity to do work. Figure 1.4 Deionization all energy are capable of doing work Distilled and deionized water are used almost ○ Work - exerting a force over a distance interchangeably. FORMS OF ENERGY Dilute solution - Can be prepared from concentrated solution All forms of energy can be converted (at least in FORMULA: principle) from one form to another. It can be explained by the Law of Conservation of Energy: the total quantity of energy in the universe is assumed constant. KINETIC ENERGY the energy produced by a moving object is one form of energy that is of particular interest to chemists RADIANT ENERGY (SOLAR ENERGY) comes from the sun and is Earth’s primary energy source EXAMPLE: heats the atmosphere and Earth’s surface, THERMAL ENERGY is the energy associated with the random motion of atoms and molecules. CHEMICAL ENERGY stored within the structural units of chemical substances its quantity is determined by the type and arrangement of constituent atoms Solubility Curve can be considered a form of potential energy because it is associated with the relative positions and A graphical relationship between the solubility and arrangements of atoms within a given substance. temperature POTENTIAL ENERGY is energy available by virtue of an object’s position ENERGY UNITS SI unit of energy is the joule (J) ○ Joule (J) - 1 kg m2/s2 British Thermal Unit (Btu) ○ widely used in several engineering disciplines 5 I Chemistry for Engineers - 1st SEMESTER  xo,navi. ○ was first defined as the amount of energy needed to raise the temperature of 1 lb of water by 1°F ○ 1 BTU = 1055 J Calorie (C) ○ originally defined as the amount of energy required to heat 1 g of water from 14.5 to 15.5°C. ○ 1 C = 4184 J ENERGY CHANGES IN CHEMICAL REACTIONS Almost all chemical reactions absorb or produce (release) energy, generally in the form of heat. HEAT the transfer of thermal energy between two bodies that are at different temperatures Figure 2.2 Types of Systems the term “heat” by itself implies the transfer of energy HEAT ABSORBED OR HEAT RELEASED EXOTHERMIC PROCESS term describing the energy changes that occur during any process that gives off heat a process. ○ transfers thermal energy to the surroundings. ○ Ex. Combustion THERMOCHEMISTRY ENDOTHERMIC PROCESS Thermochemistry - is the study of heat change in heat has to be supplied to the system chemical reactions. ○ Ex. Photosynthesis, cooking SYSTEM AND SURROUNDINGS INTRODUCTION TO THERMODYNAMICS System Thermocheistry ○ the specific part of the universe that is of ○ part of a broader subject called interest to us thermodynamics ○ includes substances involved in chemical ○ is the study of heat change in chemical and physical changes reactions. Surroundings ○ the rest of the universe outside the system. THERMODYNAMICS scientific study of the interconversion of heat and other kinds of energy study changes in the state of a system ○ State of a System - defined by the values of all relevant macroscopic properties ○ State Functions - properties that are determined by the state of the system FIRST LAW OF THERMODYNAMICS based on the law of conservation of energy states that energy can be converted from one form to another, but cannot be created or destroyed Change in the internal energy - can test the validity of the law Figure 2.1 System and Surroundings ○ Change in internal Energy of a System Components OPEN SYSTEM kinetic energy component consists of various types of molecular exchange mass and energy motion and the movement of usually in the form of heat with its surroundings electrons within molecules CLOSED SYSTEM potential energy is determined by the attractive interactions between which allows the transfer of energy (heat) but not electrons and nuclei and by mass. repulsive interactions between electrons and between nuclei in ISOLATED SYSTEM individual molecules, as well as by does not allow the transfer of either mass or energy interaction between molecules. 6 I Chemistry for Engineers - 1st SEMESTER  xo,navi. CHANGE IN INTERNAL ENERGY: △𝑈 = 𝑈𝑓 − 𝑈𝑖 Where: △𝑈 is the change in internal energy 𝑈𝑓 is the final internal energy 𝑈𝑖 is the initial internal energy △𝑈 = 𝑞 + 𝑤 Where: △𝑈 is the change in internal energy Figure 2.3 The expansion of gas against constant external 𝑞 is the heat pressure. The gas is in cylinder filled with a weightless 𝑤 is the work movable piston. FORMULA OF WORK UNITS OF WORK Table 2.1 Sign Conventions for work and heat is J since the Equation 2.2 is atm L = J we need to convert it. Conversion Factor - 1 atm L = 101.3 J WORK In thermodynamics, work has a broader meaning that includes: ○ mechanical work ○ electrical work ○ surface work MECHANICAL WORK One way to illustrate mechanical work is to study the HEAT expansion or compression of a gas. Like work, heat is not a state function. EXAMPLES: another component of internal energy ○ Breathing and exhaling air ○ internal combustion engine of the automobile HEAT CAPACITY AND CALORIMETRY ○ successive expansion and compression of the cylinders due to the combustion of the HEAT CAPACITY (C) gasoline-air mixture provide power to the determined by both the type and amount of substance vehicle that absorbs or releases heat an Extensive Property - its value is related to the amount of the substance 7 I Chemistry for Engineers - 1st SEMESTER  xo,navi. FORMULA: SPECIFIC HEAT CAPACITY (c) depends only on the type of substance absorbing or releasing heat an Intensive Property - the type, but not the amount, CALORIMETRY of the substance is all that matters. used to measure amounts of heat transferred to or the unit for c is J/g °C from a substance. Molar Heat Capacity - heat capacity per mole of a technique we can use to measure the amount of heat particular substance and has units of J/mol °C involved in a chemical or physical process CALORIMETER a device used to measure the amount of heat involved in a chemical or physical process. Figure 2.4 Table 2.2 Specific heat capacity of common substances FORMULA: EXAMPLE: Figure 2.5 (a) heat, q, is transferred from the hot metal, M, to cool water, W, until (b) both are at the same temperature. FORMULA: 8 I Chemistry for Engineers - 1st SEMESTER  xo,navi. EXAMPLE: SUMMARY OF FORMULAS: Molality: 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 𝑚= 𝐾𝑔 𝑜𝑓 𝑆𝑜𝑙𝑣𝑒𝑛𝑡 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 = 𝑚 × 𝑘𝑔 𝑜𝑓 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 𝐾𝑔 𝑜𝑓 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 = 𝑚 Weight Percent: Volume Percent: SUMMARY OF FORMULAS: SI Derived Units: Parts Per Million: Temperature: Parts Per Billion: Molarity: 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 𝑀= 𝐿𝑖𝑡𝑒𝑟𝑠 𝑜𝑓 𝑆𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 = 𝑀 × 𝐿𝑖𝑡𝑒𝑟𝑠 𝑜𝑓 𝑆𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 𝐿𝑖𝑡𝑒𝑟𝑠 𝑜𝑓 𝑆𝑜𝑙𝑢𝑡𝑖𝑜𝑛 = 𝑀 9 I Chemistry for Engineers - 1st SEMESTER  xo,navi. SUMMARY OF FORMULAS: SUMMARY OF FORMULAS: Concentration: Calorimetry: PADAYON FUTURE ENGINEERS!!! SPECIAL NOTES: Hi! Yung binigay na Pointers To Review ni Ma’am ay may highlight na For Concept - Light Yellow …….. sa topic may highlight Change in Internal Energy: For Computations - Dark Yellow ……… at sa △𝑈 = 𝑈𝑓 − 𝑈𝑖 formula may highlight. Where: △𝑈 is the change in internal energy 𝑈𝑓 is the final internal energy 𝑈𝑖 is the initial internal energy △𝑈 = 𝑞 + 𝑤 Where: △𝑈 is the change in internal energy 𝑞 is the heat 𝑤 is the work Work: Heat: 𝑞 = 𝐶△𝑇 𝑞 △𝑇 = 𝐶 Specific Heat: 𝑞 𝑚 = 𝑐△𝑇 𝑞 𝑐 = 𝑚△𝑇 𝑞 △𝑇 = 𝑚𝑐 10 I Chemistry for Engineers - 1st SEMESTER