10 Chem Chemistry Ch.2 Study Guide

Energy and Matter: Energy: Energy: the capacity to do work or to produce heat. Forms of Energy: Radiant Energy: Energy from the sun Kinetic Energy: Energy of motion, energy carried by objects in motion Potential Energy: Stored energy • Electrical Potential energy is the energy that exists when objects with different electrical chargers are separated. • Chemical Potential energy exists because of the arrangement of the particles that make up a substance. Measuring Energy: Calorie: is the most common unit used to measure energy. 1 calorie is the amount of heat needed to raise the temperature of 1 gram of calories. Joule: The SI unit of energy. The joule is named for James Prescott Joule , an English physicist who made pioneering advances in our understanding of energy. 1 cal = 4.184 J Law of Conservation of Energy: States: In any process, energy is neither created nor destroyed. • Energy is transferred from one object to another or transformed from one kind of energy to another. • The Law of Conservation of Energy is very general and it doesn’t apply to the processes that occur in the sun (nuclear energy.) The Energy Crisis: • Our society depends on chemical energy in two substances: coal and petroleum. • So-called fossil fuels are where 90 percent of our energy comes from • Other sources of energy such as energy from the sun and wind are less convenient and more expensive making them less popular.

Temperature: The Fahrenheit and Celsius Temperature Scales: • Gabriel Fahrenheit made good thermometers and devised his own temperature scale. • Swedish Astronomer Anders Celsius created the Celsius scale that was more compatible with the metric system. Fahrenheit Celsius Boiling Point: 212oF Boiling Point: 100oC Melting Ice: 0oC Melting Ice: 32oF

Room Temp: 21oC Room Temp: 70oF The Kelvin Temperature Scale: • The SI scale used to measure temperature is the Kelvin scale. Named after the British Physicist William Thomson, Lord Kelvin. • Difference between the Kelvin scale and the Celsius scale is the point of absolute zero. • Absolute Zero: The point at which th emotion of particles of matter- their kinetic energy- ceases. • Co = K-273

Matter: Everything is made of matter. Matter: is anything that has mass and volume. States of Matter: Solid: Holds a particular shape and has a definite volume. Liquid: Does not hold a particular shape but has a definite volume and takes the shape of its container. Gas: Has no definite shape of volume. It expands to the volume available in its container. States can be changed through heating and cooling. Properties of Matter: Physical Properties: Characteristics of a substance that can be observed without altering the identity of the substance are called physical properties. Chemical Properties: Characteristics of a substance that cannot be observed without altering the substance. Changes in Matter: Physical Changes: Changes in matter which to not alter the identity of a substance. Chemical Changes: Chemical reactions that do alter the identity of a substance. Conservation of Matter: • Antoine Lavoisier made a universal statement that applies to all branches of science. • Law of Conservation of Matter:Matter, like energy, is neither created nor destroyed in any process.

Elements and Compounds: Elements: Element: A substance that cannot be separated into simpler substances by a chemical change. • Elementsare listed together in a periodic table. Compounds: Compound: when two or more elements combine in a chemical reaction. Distinguishing Between Elements and Compounds: Pure Substances: Elements and compounds • Every element has a set of unique chemical and physical properties. • Electrolysis: helped chemists after Lavoiser to distinguish between elements and compounds. Electrolysis tears apart an element with electricity.

Mixture: Mixture: A blend of two or more pure substances.

Types of Mixtures: Heterogeneous Mixture: A mixture that has visibly different parts. Homogeneous Mixture: Mixtures that don’t contain visibly different parts. Separating the Components of a Mixture: Heterogeneous Mixture Homogeneous Mixture Filtration Distillation, crystallization, and chromatography • • •

Distillation; takes advantages of different boiling points to separate solid impurities from water and other liquids. Crystallization: Limited to liquid solutions, produces solids are a very high level of purity Chromatography: Separating a substance by allowing it to flow along with another stationary substance.