Mastering Chemistry- Chapter 1

matter

anything that has mass and takes up space

atom

A submicroscopic particle that constitutes the fundamental building block of ordinary matter; the smallest identifiable unit of an element. (1.1)

molecule

Two or more atoms joined chemically in a specific geometrical arrangement. (1.1)

chemistry

The science that seeks to understand the properties of matter by studying the structure of the particles that compose matter. (1.1)

substance

A specific instance of matter. (1.2)

state

A classification of a form of matter as a solid, liquid, or gas. (1.2)

composition

Refers to the type of particles that compose matter; by composition is one way to classify matter. (1.2)

solid

The state of matter in which atoms or molecules are packed close to one another in fixed locations with definite volume. (1.2)

gas

The state of matter in which atoms or molecules have a great deal of space between them and are free to move relative to one another; lacking a definite shape or volume, a gas conforms to the shape and volume of its container. (1.2)

liquid

The state of matter in which atoms or molecules pack about as closely as they do in solid matter but are free to move relative to each other, resulting in a fixed volume but not a fixed shape. (1.2)

pure substance

A substance composed of only one type of atom or molecule. (1.2)

mixture

A substance composed of two or more different types of atoms or molecules that can be combined in variable proportions. (1.3)heterogeneous mixture, A mixture in which the composition varies from one region to another. (1.2)

homogeneous mixture

A mixture with the same composition throughout. (1.2)

solute

a pure substance dissolved in another pure substance which makes a solution

solvent

the pure substance that another pure substance is dissolved IN to make a solution

absorption

the physical phenomenon of light getting absorbed by certain substances

absorbance

the mathematical parameter that measures the phenomenon of light getting absorbed by certain substances

incident beam

the beam entering a sample

transmitted beam

the beam exiting the sample

empirical

based on observation or experiment

hypothesis

A tentative interpretation or explanation of an observation. A good hypothesis is falsifiable. (1.3)

experiment

A highly controlled procedure designed to generate observations that may support a hypothesis or prove it wrong. (1.3)

scientific law

A brief statement or equation that summarizes past observations and predicts future ones. (1.3)

law of conservation of mass

The law stating that matter is neither created nor destroyed in a chemical reaction. (1.3) (Lavoisier)

theory

A proposed explanation for observations and laws, based on well-established and tested hypotheses; a theory presents a model of the way nature works and predicts behavior beyond the observations and laws on which it was based. (1.3)

chemical reaction

A process by which one or more substances are converted to one or more different substances; see also chemical change. (1.5, 7.3)

reactant

A starting substance in a chemical reaction; reactants appear on the left-hand side of a chemical equation. (7.3)

product

A substance produced in a chemical reaction; products appear on the right-hand side of a chemical equation. (7.3)

law of definite proportions

The law stating that all samples of a given compound have the same proportions of their constituent elements. (1.5) (Proust)

law of multiple proportions

The law stating that when two elements (A and B) form two different compounds, the masses of element B that combine with one gram of element A can be expressed as a ratio of small whole numbers. (1.5) (Dalton)

atomic theory

The theory that each element is composed of tiny indestructible particles called atoms, that all atoms of a given element have the same mass and other properties, and that atoms combine in simple, whole-number ratios to form compounds. (1.5)

atomic number (Z)

The number of protons in an atom; the atomic number defines the element. (1.8)

periodic table

The table that arranges all known elements in order of increasing atomic number; elements with similar properties generally fall into columns on the periodic table. (1.8)

ion

An atom or molecule with a net charge caused by the loss or gain of electrons. (1.8),

isotope

One of two or more atoms of the same element with the same number of protons but different numbers of neutrons and consequently different masses. (1.8)

mass number (A)

The sum of the number of protons and neutrons in an atom. (1.8)

natural abundance

The relative percentage of a particular isotope in a naturally occurring sample with respect to other isotopes of the same element. (1.8)

periodic table

The table that arranges all known elements in order of increasing atomic number; elements with similar properties generally fall into columns on the periodic table. (1.8)

anion

A negatively charged ion. (1.8)

cation

A positively charged ion. (1.8)

chemical symbol

A one- or two-letter abbreviation for an element that is listed directly below its atomic number on the periodic table. (1.8)

mass spectrometry

An experimental method of determining the precise mass and relative abundance of isotopes in a given sample using an instrument called a mass spectrometer. (1.9)

atomic mass (atomic weight)

The average mass in amu of the atoms of a particular element based on the relative abundance of the various isotopes; numerically equivalent to the mass in grams of one mole of the element. (1.9)

molar mass

The mass in grams of one mole of atoms of an element; numerically equivalent to the atomic mass of the element in amu. (1.10)

mole (mol)

A unit defined as the amount of material containing 6.0221421×1023 (Avogadro's number) particles. (1.10)

Avogadro's number

The number of C 12 atoms in exactly 12 g of C 12; equal to 6.0221421×1023. (1.10)