Chemistry The Study of Matter

Chemistry is the study of matter and their interactionsChemistry is the study of matter and their interactions –The substances of which physical substances are made The study of modern chemistry began in the 1700’sThe study of modern chemistry began in the 1700’s For thousands of years prior, alchemists were the main students of matter and their interactionsFor thousands of years prior, alchemists were the main students of matter and their interactions –Alchemy was a little science mixed with a lot of philosophy and spiritualism The Basics

Matter is classified based on its state or phase The 4 states/phases are: 1.Solid 2.Liquid 3.Gas 4.Plasma

Solid Particles are: arranged in regular, repeating patterns held firmly in place are vibrating

Liquid Particles : Flow easily around one another Kept from flying apart by attractive forces between them Liquids assume the shape of their container

Gas Particles fly around at great speeds in all directions Attractive forces between particles are insignificant Will completely fill its container

Plasma Atoms lose their electrons at high temperatures A mixture of nuclei and electrons By far the most common state of matter in the universe

Kinetic-Molecular Theory Describes solids, liquids and gases All matter consists of extremely small particles Particles are in constant, random motion The higher the temperature, the faster the particles are moving (more kinetic energy) –The ‘energy of motion’

Solids Particles have lower kinetic energy than liquids (move at low speeds) Particles are close together and restricted to specific locations Particles are arranged with a high degree of regularity

Liquids Particles have a higher kinetic energy than solids (move at faster speeds) Particles are close to each other but can move past one another

Gases Particles have high kinetic energy (move at high speeds) Particles move freely in random, straight-line patterns Little interaction between particles

Plasma Higher energy than a gas Nuclei and electrons are moving around separately from each other Can be found in stars, lightning, fluorescent lights, etc.

Pure Substances Elements All atoms that make up an element are the same They exhibit unique chemical & physical properties They cannot be broken down into simpler substances All known elements are found on the periodic table

Compounds Can contain two or more different elements in a fixed proportion Exhibit unique chemical & physical properties Identified with chemical formulas –Ex. H 2 O (water) CO 2 (carbon dioxide)

Mixtures Made up of a combination of elements and/or compounds Solutions/Homogeneous Mixtures the chemical & physical properties of the substance are the same throughout –Ex. Salt water, milk, soft drinks

Heterogeneous Mixtures Part of the substance exhibits different chemical & physical properties than other parts –Ex. Chocolate chip cookies Oil and water

Properties of Matter Distinguishing features that let us identify what we’re examining All matter has 2 different kinds of distinguishing features: 1.Physical properties 2.Chemical properties

Physical Properties Can be observed without altering chemical make-up of the substance Original substance can be retrieved –Ex. Hardness Boiling point Color Odor Melting point Solubility

Chemical Properties Can be observed when a substance reacts with another substance Original substance will be ‘lost’ Done by conducting chemical tests –Ex. Flame test – used to determine type of metal Lime water test – used to test for CO 2

“Kinds” of Matter matter pure substance mixtures compounds elements solutions heterogeneous mixtures