Chapter 2 Energy and Matter

2-1 Energy Energy – is the capacity to do work. Forms of Energy Work – is the ability to move an object over a distance against a resisting force. Forms of Energy Light Mechanical Chemical Heat Electrical

2-1 Energy Classifications of Energy Radiant Energy Potential Energy Energy in which little matter is needed. Potential Energy Stored energy Kinetic Energy Energy of motion

2-1 Energy Measuring Energy Units of energy Joules (J) – S.I. Unit of energy. calorie (cal) – amount of heat needed to raise the temperature of 1 g of water by 1oC. Calorie(Cal) – dietary calorie. Devices used in measuring Heat Energy Standard calorimeter Bomb calorimeter

2-1 Energy Converting units of energy 1 cal = 4.184 J 1 Cal = 1000 cal 1 kJ = 1000 J How many kJ are in 2.45 x 108 cal?

2-1 Energy Practice: 1) Convert the following to calories (cal): a) 900 J b) 2 Cal 2) Convert the following to joules (J): a) 2.00 cal b) 220 Cal

2-1 Energy Law of Conservation of Energy Energy Crisis In any process, energy is neither created nor destroyed. Energy Crisis “Running out of energy?” How can it be?

2-1 Energy Heat Capacity and Specific Heat Heat Capacity – amount of heat needed to raise the temperature of a sample 1oC. Units (J/oC) Will change depending upon the mass of the object. More mass more heat capacity.

2-1 Energy Specific Heat Capacity Amount of heat needed to raise the temperature of 1g of a substance by 1oC. Larger value = Longer time to Heat Specific Heat of Water = 4.184 J/goC = 1 cal/goC Cp = specific heat q = heat m = mass T = change in temp

2-1 Energy Heat Capacity vs. Specific Heat Capacity Aluminum has a specific heat capacity of.899 J/goC. How much heat will it take to raise 1 g of Al by 1oC? .899J Will 500g of Al or 100g have a greater heat capacity? 500g, more mass more heat capacity. Will 500g of Al or 100g have a greater specific heat capacity? Neither, aluminum always has a specific heat of .899j/goC

2-1 Energy What is the specific heat of a 550g substance, that gains 1200J of heat, as it increases in temperature from 25oC to 40oC?

2-2 Temperature Temperature – is the degree of hot or cold, determined by a thermometer. Average kinetic energy of the particles in a sample. Hot or Cold, are relative terms, dependent on a difference in temperature.

2-2 Temperature Temperature Scales Fahrenheit – Degreed scale based upon Gabriel Fahrenheit. Water Boils at 212oF Freezes at 32oF Celsius – Degreed scale based upon Anders Celsius. Metric system. Boils at 100oC Freezes at 0oC

2-2 Temperature Temperature Scales Kelvin – Absolute scaled, developed by William Thomson, Lord Kelvin. Based upon Absolute Zero. No negatives. Lowest temperature possible, in theory. Water Boils at 373 K Freezes at 273 K

2-2 Temperature Converting temperatures: oC + 273 = kelvin K – 273 = oC

2-2 Temperature Sample Problems Convert the following to kelvins: 1) 100oC 2) –120oC Convert the following to Celsius: 1) 100 K 2) 900 K

2-2 Temperature Answers Problems Convert the following to kelvins: Convert the following to Celsius: 1) –173oC 2) 627oC

2-3 Matter Anything that has mass and volume.

2-3 Matter States of Matter Solid – definite shape, and volume. Particles are tightly packed together, but still can vibrate or rotate. Liquid – Indefinite shape but definite volume. Particles are loosely spaced group, that move together. Gases – Indefinite shape and volume. Individualized particles that move rapid and randomly. Plasma – Similar to gases but have charged particles.

2-3 Matter Changes in States Heating – makes the particles move faster. Solid  Liquid  Gas  Plasma Cooling – makes the particles move slower. Plasma  Gas  Liquid  Solid

2-3 Matter Properties – Characteristics that help describe an object. Physical Properties – only describe the outer appearance of an object. Will not alter the object. Color, size, shape, mass, etc. Chemical Properties – describes the internal make-up of an object. Alters the object. Chemical reactions: flammability, solubility, decomposition, etc.

2-3 Matter Changes in Matter Physical Change – Alters the outer appearance of a substance without changing what it is. Chemical Change – Alters the internal make-up of a substance, it is no longer the same substance.

2-3 Matter Indications of chemical change Light or Heat (release of energy) Bubbles or gas Formation of a solid from a solution. Precipitate (PPT)

2-3 Matter Conservation of Matter Matter, like energy, can’t be created nor destroyed in any process.

2-4 Pure Substance Homogeneous sample of matter, that can not be separated by physical means. Can only, if at all, be separated by chemical means.

2-4 Pure Substance Elements Substance that can not be separated into simpler substances by physical or chemical change. 1 – 2 letter symbol, 1st letter is always capitalized. Symbol is normally the 1st or 1st +2nd letters of the elements English or Latin name.

2-4 Pure Substance Compounds Substance that contains two or more elements, which can be separated by chemical change. Identifying elements in a compound Every capital letter indicates a new element. Na2CO3 Na – Sodium, C – Carbon, and O - Oxygen

2-4 Pure Substance Practice: Identify the number and type of elements in the following compounds: 1) NaC2H3O2 2) PbCl2 3) KMnO4 4) HClO3 1) 1 Sodium, 2 Carbon, 3 Hydrogen, 2 Oxygen 2) 1 Lead, 2 Chlorine 3) 1 Potassium, 1 Manganese, 4 Oxygen 4) 1 Hydrogen, 1 Chlorine, 3 Oxygen

2-4 Pure Substance Law of Definite Composition A compound has the same ratio of elements by mass, no matter how large of a sample given. Example – Sugar has 42.1% Carbon 51.4% Oxygen 06.5% Hydrogen by mass.

2-5 Mixtures Blend of two or more pure substances, by which each can be obtained through a physical separation.

2-5 Mixtures Heterogeneous Homogeneous (Solutions) Mixture that has two or more “phases,” or visible different parts. Homogeneous (Solutions) Mixture that has only one phase. Stainless Steel Carbon, Iron, Nickel, & Chromium

2-5 Mixtures Separation of mixtures Filtration Distillation Crystallization Chromatography Physical property (ex. Magnetic)

2-5 Mixtures Summary of Matter Matter can be classified as: Pure Substances Mixtures Differences in the two types of matter: Whether it can be separated physically or chemically, if at all.

Chapter 2 Summary Matter NO Can be separated physically? YES Pure Substance Mixture One Phase? Can be separated chemically? YES NO YES NO Elements Compounds Homogeneous Heterogeneous

Granite Plastic and water Heterogeneous mixture Heterogeneous mixture Solid Gold Pure Substance (element) Brass Homogeneous mixture Gold Ore Iron Sulfide Pure Substance (compound) Heterogeneous mixture

Origins of Element Symbols 11 Elements have an atomic symbol that doesn’t seem to match their name. Originally named in Latin Na – Sodium (Natrium) K – Potassium (Kalium) Fe – Iron (Ferrum) Pb – Lead (Plumbum) Au - Gold (Aurum) Ag – Silver (Argentum) Sn – Tin (Stannum) Hg – Mercury (Hydrargyrum) Sb – Antimony (Stibium) Cu – Copper (Cuprum) One originally named in Germany W – Tungsten (Wolfram)