States of Matter and Atomic Theory

These flashcards cover key concepts and definitions related to the states of matter, atomic theory, and basic chemistry principles as outlined in the lecture notes.

What is matter?

Matter is anything that occupies space and has mass.

What are the three most common states of matter?

Solid, liquid, and gas.

What is a characteristic of solids at the molecular level?

Solids are tightly packed, have limited atomic or molecular motion, and often exhibit a crystalline structure.

What is the primary difference between liquids and solids?

Liquids have more atomic or molecular motion than solids and do not have a definite structure.

What does the term 'isotropic' mean in the context of matter?

Isotropic describes a state of matter where there is no definite order in how atoms or molecules are arranged.

What is an amorphous solid?

An amorphous solid is a solid that lacks a long-range order in its atomic structure.

What is the flow nature of gases compared to solids and liquids?

Gases are much less condensed than solids and liquids, have no definite shape or volume, and can flow freely.

Define the law of conservation of mass.

The law of conservation of mass states that matter can neither be created nor destroyed, but it can change form.

What is an isotope?

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

What is Avogadro's number?

Avogadro's number is approximately 6.02 x 10²³, and it defines the number of atoms or molecules in one mole.

What is the difference between atomic mass and mass number?

Mass number is the sum of protons and neutrons in an atom, while atomic mass is the average mass of an atom considering all isotopes.

What is the significance of hydrogen in relation to isotopes?

Hydrogen has three isotopes: protium (1 proton, 0 neutrons), deuterium (1 proton, 1 neutron), and tritium (1 proton, 2 neutrons).

What are allotropes?

Allotropes are different physical forms of the same element, such as graphite and diamond for carbon.

What are cations and anions?

Cations are positively charged ions, while anions are negatively charged ions.

What are physical properties in chemistry?

Physical properties are characteristics of substances that can be observed or measured without changing the identity of the substance.

What is a homogeneous mixture?

A homogeneous mixture is a mixture in which the composition is uniform throughout, such as strained tea.

What is a chemical reaction?

A chemical reaction is a process that involves the transformation of one or more substances into different substances.

What is the significance of the periodic table?

The periodic table organizes elements based on their atomic number and chemical properties, showing periodic trends.

Name a key feature of gases in terms of volume and shape.

Gases have variable shape and variable volume, expanding to fill their container.