Chemistry Lesson 1 PDF

CHEMISTRY: LESSON 1 The state of matter observed for a particular substance depends on its: What is Chemistry? -...

CHEMISTRY: LESSON 1 The state of matter observed for a particular substance depends on its: What is Chemistry? - Temperature - The field of study concerned with the - Surrounding Pressure characteristics, composition, and - Strength of the forces holding its transformations of matter. structural particles together. Matter * Water can be found in all three states simultaneously* - Anything that has mass and occupies space. Property *Mass refers to the amount of matter - A characteristic that can be used to present in a sample* describe a substance - Substances have both physical and - Includes all things – both living and chemical properties nonliving Transformations - examples: plants, soil, air, and bacteria - A change in the properties of matter with time. - Various forms of energy such as heat, - There are physical and chemical light, and electricity are not changes. considered to be matter. - The universe is composed entirely of Substances have both physical and chemical matter and energy. properties. Physical Properties: Density, color, and melting point are physical properties of matter. Observing a physical property can be done without altering the makeup of a substance. -solid Extensive/ -liquid Extrinsic -gas PHASE/STATE PROPERTIES Intensive/ -plasma S Intrinsic MATTER KINDS OF CHANGES -Physical -Chemical  Chemical Properties: Chemical Physical Changes composition, what matter is made of, and - Changes in physical properties (such chemical reactivity, how matter behaves, are as size, shape, and density) or chemical properties. Observing a chemical changes in the state of matter without property alters the substance. an accompanying change in composition. - No new substances are formed. Physical property Examples: - Characteristics of a substance that can be observed without changing the - Tearing of paper basic identity of the substance. - Change of ice into water - Heating platinum wire - Color, odor, physical state, melting - Change of water into steam point, boiling point, and hardness - Does not alter the chemical makeup of a substance Properties of - Chemical reactivity is unchanged matter - Changes in state, Changes in particle size, and the formation / separation of Are these properties determined mixture are all example of physical no without changing the identity of yes change. the substance? Chemical Physical Properties Properties no Do the properties yes How does the depend on amount substance react to of substance? the presence of: Intensive Physical Extensive Physical - Air property property - Acid - Color - Mass - Base - shape - Volume - Water - Melting point - Length - Other - boiling point - shape chemicals - density - state Chemical Changes - Most often the changes result from the reaction of a substance with one - Alters the makeup of a substance or more other substance. - Reactivity changes with the formation - Sometimes energy (like heat or light) of new substances. can trigger a change (decomposition). - Heat, light, or electrical energy is often emitted or absorbed. - Potassium reacting with water is an EXERCISE: example of a chemical change. Classify each of the following as a physical or Example: chemical property. - Nickel, a solid metal, is mixed with a A) A marshmallow gets black when colorless solution of hydrochloric roasting in a campfire: Chemical acid in a test tube. property - The nickel is slowly eaten away, the B) Zinc is a solid at room temperature: colorless solution turns green, and a Physical property colorless gas bubbles out of the test C) When rubbing alcohol is rubbed on tube. your skin, it evaporates very quickly: Physical property CONCEPT CHECK: To measure the boiling point of a substance, a CONCEPT CHECK: liquid must be changed into a gas. Why is Which of the following is a homogenous boiling point considered a physical property mixture? when a gas’ appearance is much different from that of a liquid? - Pure water - Gasoline Although the appearance is different, - Jar of jellybeans the substance is still the same. Its chemical - Soil identity has not changed. - Copper metal Chemical property Element - Describe the ability of a substance to - A pure substance that cannot be form new substances, either by broken down into simpler pure reaction with other substances, substances by chemical means such decomposition at a high temperature, as a chemical reaction, an electric or flammability. current, heat, or a beam of light. - Characteristics of a substance that Example: gold, silver, and copper describes the way the substance undergoes, or resists change to form a new substance. Example: copper object turns green in air  Compound To classify a sample of matter - A pure substance that can be broken 1) Does the sample of matter have the down into two or more simpler pure same properties throughout? substances by chemical means. A pure substance can be either an element or compound 117 known elements: PURE SUBSTANCE - 88 of the elements occur naturally - 29 of the elements have been Only one substance synthesized present Abundance of elements (in Atom percent) in the universe ELEMENT COMPOUND - 91% - Hydrogen Cannot be broken down Can be broken down into - 9% - Helium into simpler substances constituent elements, by -