chem-study guide

Chemistry

The study of matter and its changes.

Scientific process

The process of seeking and understanding the underlying principles of nature, involving the accumulation of knowledge about the physical world.

Scientific Hypothesis

A testable explanation of observed data.

Scientific Law

A summary of large amounts of scientific data that describes natural phenomena, often stated mathematically.

Scientific Theory

A set of tested hypotheses that explain natural phenomena; the best current explanation for a given phenomenon.

Applied Research

Research focused on solving specific problems in industry or the environment.

Basic Research

Research conducted to acquire knowledge for its own sake.

Mass

The measure of the amount of matter in an object.

Weight

The measure of the gravitational force on the matter in an object.

Law of Conservation of Mass

Matter is neither created nor destroyed during a chemical reaction; the total mass of the products equals the total mass of the reactants.

Law of Definite Proportions

A chemical compound always contains the same elements in definite proportions.

Law of Multiple Proportions

When two elements combine in different ways, they do so in ratios of small whole numbers.

Dalton's Atomic Theory

All matter is composed of indestructible particles called atoms.

Isotopes

Atoms of the same element with different masses.

Atomic Mass

The mass of one mole of a substance, known as the molar mass.

Electrolysis

Chemical reactions caused by electricity.

Anode

The positive electrode in an electrochemical cell.

Cathode

The negative electrode in an electrochemical cell.

Oxidation

The process when an element combines with oxygen, resulting in a gain of oxygen.

Reduction

The process that is opposite to oxidation; it involves the loss of oxygen.

Catalysts

Substances that speed up a chemical reaction or lower the activation energy needed for the reaction without being consumed.

Polymers

Large macromolecules made up of smaller units called monomers.

HDPE

High-density polyethylene, linear molecules with good tensile strength.

LDPE

Low-density polyethylene, branched molecules that are waxy and bendable.

Vulcanization

A process where rubber is treated with sulfur to harden it.