Exam 1 study

Chemistry 1630 Lecture

Atoms

Basic units of matter that consist of a nucleus and are the building blocks of all elements.

Molecules

Two or more atoms chemically bonded together, which can be the same or different elements.

Elements

Pure substances that cannot be broken down into simpler substances by chemical means, consisting of only one type of atom.

Compounds

Substances formed by the chemical combination of two or more different elements in fixed proportions.

Mixtures

Combination of two or more substances in which each substance retains its individual properties and can be separated by physical means.

Homogeneous matter

Matter that has a uniform composition and consistency throughout.

Heterogeneous matter

Matter that consists of visibly different substances or phases.

Physical change

Change that does not alter the chemical composition of a substance, such as state, size, or shape.

Chemical change

A change that results in the formation of new chemical substances.

Law of Conservation of Matter

States that matter cannot be created or destroyed in a closed system.

Precision

Refers to how close repeated measurements are to each other.

Accuracy

Refers to how close a measurement is to the true value.

Scientific notation

A method of expressing numbers as a product of a coefficient and a power of ten.

Significant figures

Digits in a number that carry meaningful information about its precision.

Density

The mass per unit volume of a substance, typically expressed in grams per liter (g/L).

Kinetic energy

Energy possessed by an object due to its motion.

Potential energy

Stored energy based on an object's position or state.

Endothermic process

A process that absorbs heat from its surroundings.

Exothermic process

A process that releases heat to its surroundings.

Atomic number (Z)

The number of protons in the nucleus of an atom, which determines the identity of the element.

Atomic mass

The weighted average mass of an element's isotopes, measured in atomic mass units (amu).

Mass number

The total number of protons and neutrons in the nucleus of an atom.

Subatomic particles

Particles smaller than atoms, including protons, neutrons, and electrons.

Metric prefixes

Standard prefixes used to denote multiples or fractions of units in the metric system.

Temperature conversion formula

The equation used to convert temperature from Celsius to Kelvin: K = °C + 273.15.