Chemistry For Engineers 1 Energy PDF

CHEMISTRY FOR ENGINEERS 1 ENERGY BASIC CONCEPTS OF CHEMISTRY 1 ENERGY 2 CHEMISTRY OF ENGINEERING MATERIALS 3 CHEMISTRY OF THE ENVIRONMENT 4 CHEMICAL SAFETY 5 SPECIAL TOPICS 1 ENERGY Introduction Heat Capacit...

CHEMISTRY FOR ENGINEERS 1 ENERGY BASIC CONCEPTS OF CHEMISTRY 1 ENERGY 2 CHEMISTRY OF ENGINEERING MATERIALS 3 CHEMISTRY OF THE ENVIRONMENT 4 CHEMICAL SAFETY 5 SPECIAL TOPICS 1 ENERGY Introduction Heat Capacity and Calorimetry Enthalpy Nuclear Chemistry and Energy Electrochemistry CHEMISTRY FOR ENGINEERS INTRODUCTION TO ENERGY  “Everything is Energy And that is all there is to it.” Albert Einstein  LEARNING OUTCOMES: The student should be able to: 1. To explain the concept of energy and its various forms. 2. To describe the nature of energy changes that accompany chemical and physical changes. 3. To describe the relationship between energy and heat.  TOPICS FOR DISCUSSION Energy Two Main Types of Energy Forms of Energy Heat Conversion of Energy Conservation of Energy Units of Energy ENERGY Energy can be described as the capacity to do work, or the ability to move or cause change in matter.  WHY DO WE STUDY ENERGY? Importance in Engineering Energy is a fundamental concept in engineering and the physical sciences. It is a key factor in designing, building, and operating systems and devices. Engineers work with energy in various forms to create innovative solutions.  TWO MAIN TYPES OF ENERGY Potential Energy stored energy. Stored in springs, batteries, food and fuel. Examples: Chemical, elastic, nuclear, electromagnetic, gravitational potential energy  TWO MAIN TYPES OF ENERGY Kinetic Energy energy of motion. The faster an object moves, the higher the energy. Examples: electrical ( flow of electrons), sound (movement of air molecules), thermal/heat (movement of atoms), any moving object (car, person, etc.)  SPECIFIC FORMS OF ENERGY Thermal Energy Chemical Energy Electrical Energy Sound Energy Light Energy Nuclear Energy  SPECIFIC FORMS OF ENERGY Thermal Energy Or Heat Energy, is a kinetic energy associated with the random motion of atoms and molecules. Example: Thermal energy from a hot stove is transferred to a metal pot and causes the water molecules to move faster increasing the temperature of the water  SPECIFIC FORMS OF ENERGY Thermal Energy Temperature is a quantitative measure of “hot” or “cold.” Movement of Ave. Kinetic Temp. Particles Energy (KE) Fast Higher KE HOTTER Slow Lower KE COLDER  SPECIFIC FORMS OF ENERGY Chemical Energy Potential energy stored in bonds of atoms and molecules. Example: Wood, coal, gasoline, and natural gas are fuels that contain chemical energy.  SPECIFIC FORMS OF ENERGY Electrical Energy Kinetic energy from the movement of charged particles called electrons. Example: Lightning, household current  SPECIFIC FORMS OF ENERGY Sound Energy Kinetic energy that is associated with vibrations of molecules in a medium. Example: A vibrating drum transfers energy to the room as sound. Kinetic energy from the moving air molecules transfers the sound energy to our eardrums. Kinetic (movement) energy in the sticks is being transferred into sound energy.  SPECIFIC FORMS OF ENERGY Light Energy Kinetic energy produced by the vibrations of electrically charged particles. It can be transmitted through a vacuum (a space without matter) Example: The energy used to cook food in the microwave  SPECIFIC FORMS OF ENERGY Nuclear Energy Potential energy that is trapped inside each atom. It can be produced either by the fusion (combining atoms) or fission (splitting of atoms) process. Example: Atomic bombs, nuclear power plants, nuclear submarines and the sun  SUMMARY: SPECIFIC FORMS OF ENERGY Thermal Energy - associated with the random motion of atoms and molecules Chemical Energy - stored in bonds of atoms and molecules Electrical Energy - movement of electrons Sound Energy - associated with vibrations of molecules in a medium Light Energy - vibrations of electrically charged particles Nuclear Energy - trapped inside each atom  HEAT the flow of thermal energy between two objects, from the warmer one to the cooler one, because of a difference in their temperatures. Thus, heat is a process and not a quantity.  HEAT Matter undergoing chemical reactions and physical changes can release or absorb heat. A reaction or change A reaction or change that releases heat is an that absorbs heat is an exothermic process. endothermic process.  CONVERSION OF ENERGY Energy Conversion is a change in energy from one form of energy to another. Any form of energy can be converted into any other form of energy. In every conversion, some energy is always converted into thermal energy.  CONVERSION OF ENERGY Energy Conversion is a change in energy from one form of energy to another.  CONVERSION OF ENERGY Conversions Involving Chemical Energy Food is digested and used to regulate body temperature Fuel is burned to cook food During photosynthesis, plants use light energy to produce new substances with chemical energy.  CONVERSION OF ENERGY Conversions Involving Electrical Energy Light bulb: electrical energy to light Microphone: electrical energy to sound energy Battery: chemical energy to electrical energy  CONSERVATION OF ENERGY Thermodynamic System is quantity of matter of fixed identity, around which we can draw a boundary. (NOTE: Concept used in line with the flow or transfer of energy)  CONSERVATION OF ENERGY Thermodynamic System The boundaries may be fixed or moveable. Everything outside the boundary is the surroundings.  CONSERVATION OF ENERGY Law of Conservation of Energy In all ordinary changes or transformation, energy can neither be created nor destroyed. Energy can be changed from one form to another, but all the different forms of energy in a system always add up to the same total amount of energy, no matter how many conversions occur.  CONSERVATION OF ENERGY Law of Conservation of Energy Conservation of energy requires that the total energy change in the system and the surrounding must be zero. ∆𝐸𝑛𝑒𝑟𝑔𝑦𝑢𝑛𝑖𝑣𝑒𝑟𝑠𝑒 = ∆[𝐸𝑛𝑒𝑟𝑔𝑦]𝑠𝑦𝑠𝑡𝑒𝑚 + ∆[𝐸𝑛𝑒𝑟𝑔𝑦]𝑠𝑢𝑟𝑟𝑜𝑢𝑛𝑑𝑖𝑛𝑔𝑠 = 0 Where: ∆ is the symbol that is used to mean change  UNITS OF ENERGY Joule (J) is the MKS or SI unit of energy, equal to the force of one Newton acting through one meter. 𝟐 𝒌𝒈 ∙ 𝒎 𝟏 𝑱 = 𝟏 𝑵𝒎 = 𝟏 = 𝟏𝑾𝒔 = 𝟏𝑽𝑨𝒔 𝒔𝟐 Watt (W) is the power of a Joule of energy per 𝑱 second 𝟏 𝑾 = 𝟏 𝒔 Energy = Power x time = 𝟏𝑽𝑨𝒔 = 𝟏𝑾𝒔 = 𝟏 𝑱  UNITS OF ENERGY Calorie (cal) is the Metric Unit of heat, equal to the amount needed to raise 1 gram of water 1 degree Centigrade. 1 calorie (cal) = 4.184 J British Thermal Unit (BTU) is the amount of heat necessary to raise one pound of water by 1 degree Fahrenheit (F). 1 BTU = 1055 J = 1.055 kJ = 252 cal  Summary of Standard Equivalent Quantities for Energy Units 𝐤𝐠∙𝐦𝟐 1 J = 1 Nm = 1 = 1 Ws = 1VAs 𝐬𝟐 1 cal = 4.184 J 1000 cal = 1 kcal 1000 J = 1 kJ 1 BTU = 1055 J = 1.055 kJ 1 BTU = 252 cal  ACTIVE LEARNING EXERCISES Fill in the following table with what kind of energy each example contains: A burning candle A glass on a table A green plant A piece of radioactive metal A cup of hot chocolate  ACTIVE LEARNING EXERCISES Name a common device used to accomplish each change: Electrical energy to thermal energy Electrical energy to sound energy Electrical energy to light energy Mechanical energy to electrical energy Chemical energy to electrical energy  ACTIVE LEARNING EXERCISES Complete combustion of 2.0 metric tons of coal to gaseous carbon dioxide releases 6.6x1010 J of heat. Convert this energy to:  Kilojoules  Kilocalories British thermal units  ACTIVE LEARNING EXERCISES Thermal decomposition of 5.0 metric tons of limestone to lime and carbon dioxide absorbs 9.0 x 106 kJ of heat. Convert this energy to: Joules Calories  ACTIVE LEARNING EXERCISES Fill in the following table with what kind of energy each example contains: A burning candle – chemical , thermal, radiant A glass on a table – potential energy A green plant – chemical A piece of radioactive metal – nuclear A cup of hot chocolate – thermal, and chemical  ACTIVE LEARNING EXERCISES Name a common device used to accomplish each change: Electrical energy to thermal energy - flat iron, hair dryer, electric cooking appliances, etc. Electrical energy to sound energy - speakers, headphones, microphones, alarms, etc. Electrical energy to light energy - fluorescent lights, light bulbs, LEDs, etc.  ACTIVE LEARNING EXERCISES Name a common device used to accomplish each change: Mechanical energy to electrical energy - generators, turbines, dynamo Chemical energy to electrical energy - batteries, fuel cells  ENRICHMENT / ASSIGNMENT ASSIGNMENT Read handouts on Heat Capacity and Calorimetry  BASIC CONCEPTS OF CHEMISTRY THANK YOU 1 ENERGY 2 CHEMISTRY OF ENGINEERING MATERIALS 3 CHEMISTRY OF THE ENVIRONMENT 4 CHEMICAL SAFETY 5 SPECIAL TOPICS