Lecture 1: Introduction to Chemistry CHY 104

Vocabulary flashcards covering key concepts from Lecture 1 notes.

Physical property

A property describing a substance without changing its chemical composition (e.g., boiling point).

Chemical property

A property describing the substance's characteristic chemical reactions (e.g., reactivity with oxygen).

Physical change

A change that does not alter the chemical composition of the substance.

Chemical change

A change that involves the conversion of reactants to products (chemical reactions).

SI units

The International System of Units, the standard set of units used in science.

metre (m)

Unit of length in the SI base units.

kilogram (kg)

Unit of mass in the SI base units.

second (s)

Unit of time in the SI base units.

kelvin (K)

Unit of temperature in the SI base units.

mole (mol)

Unit of amount of substance in the SI base units.

ampere (A)

Unit of electric current in the SI base units.

candela (cd)

Unit of luminous intensity in the SI base units.

SI prefixes

Prefixes used with SI units to describe very large or very small numbers.

kilo (k)

Multiplier 10^3 (1,000).

mega (M)

Multiplier 10^6 (1,000,000).

giga (G)

Multiplier 10^9 (1,000,000,000).

nano (n)

Multiplier 10^-9 (0.000000001).

micro (μ)

Multiplier 10^-6 (0.000001).

deci (d)

Multiplier 10^-1 (0.1).

centi (c)

Multiplier 10^-2 (0.01).

milli (m)

Multiplier 10^-3 (0.001).

pico (p)

Multiplier 10^-12 (0.000000000001).

exa (E)

Multiplier 10^18.

femto (f)

Multiplier 10^-15.

atto (a)

Multiplier 10^-18.

uncertainty (last digit)

In a measured value, the last reported digit is uncertain; more digits imply greater certainty.

significant figures

Rules for identifying meaningful digits in a measurement (nonzero digits, interior zeros; leading zeros are not significant; trailing zeros depend on decimal presence).

decimal places rule (addition/subtraction)

Result has the same number of decimal places as the quantity with the fewest decimal places.

significant figures rule (multiplication/division)

Result has the same number of significant figures as the factor with the fewest significant figures.

mantissa

The decimal part of a logarithm; its significant figures correspond to the number of significant digits in the original value.

accuracy

Closeness of a measured value to the true or accepted value.

precision

How close a series of measurements are to one another; repeatability.

dimensional analysis

Unit conversion method used to ensure units cancel and final units are correct.

ion

A charged species formed when an atom gains or loses electrons.

cation

Positively charged ion.

anion

Negatively charged ion.

Dalton's atomic theory

Elements are composed of atoms; atoms combine in simple whole-number ratios; atoms of a given element are alike; atoms are not created or destroyed in reactions.

nucleus

The small core containing most of the atom's mass and all its positive charge.

electron

Negatively charged subatomic particle with very small mass.

proton

Positively charged subatomic particle in the nucleus.

neutron

Electrically neutral subatomic particle in the nucleus.

Atomic number (Z)

Number of protons in the nucleus; defines the element.

unified atomic mass unit (u)

1/12 the mass of carbon-12; unit for atomic mass.

chemical symbol

One- or two-letter abbreviation for an element.

Big Bang theory

Universe began in a hot, dense state and expanded; first atomic nuclei (H and He) formed.

stellar nucleosynthesis

Fusion processes in stars forming heavier elements up to iron.

nebula

Clouds of gas and dust where stars form.

supernova

Exploding star that spreads elements through space.

periodic table

Organization of elements by properties; includes atomic number and molar mass.

main-group elements

Elements in the s- and p-blocks of the periodic table.

transition metals

Metals in the d-block of the periodic table.

nonmetals

Elements with properties opposite to metals; generally poor conductors.

metalloids

Elements with properties between metals and nonmetals.

molar mass

Mass per mole of a substance, usually expressed in g/mol.