States of Matter and Properties

States of Matter

• Solids have a definite volume and shape, their particles are tightly packed in a regular three-dimensional array.
• Liquids have a definite volume but take the shape of their container, their particles are close together and can move around.
• Gases have no definite volume or shape, they fill the entire container they are in, their particles are far apart and move randomly.

Physical/Chemical Properties and Changes

• Physical properties can be observed or measured without changing the composition of the substance (e.g., boiling point, melting point, color, odor).
• Physical changes alter the substance's appearance but not its chemical composition (e.g., melting ice, boiling water).
• Chemical properties describe how a substance can be converted into another substance (e.g., flammability, reactivity with acids).
• Chemical changes/reactions convert one substance into another, usually not reversible (e.g., burning paper, metabolizing food).

Pure Substances and Mixtures

• Pure substances consist of only one component, with a constant composition regardless of sample size or origin (e.g., water, table sugar).
• Mixtures contain more than one substance, with a composition that can vary (e.g., a mixture of sand and water).

Elements and Compounds

• Elements are pure substances that cannot be broken down into simpler substances by chemical means.
• Compounds are pure substances formed by chemically combining two or more elements.

Matter

• Matter is anything that has mass and takes up space.

Chemistry

• Chemistry is the study of matter, its composition, properties, and transformations.

Significant Figures

• All nonzero digits are significant.
• Zeros between nonzero digits are significant.
• Zeros at the end of a number with a decimal point are significant.
• Zeros at the beginning of a number are not significant.
• The significant figures in a calculation depend on the number with the fewest significant figures in the calculation.

Scientific Notation

• A way to express very large or very small numbers using powers of 10.

Sig Figs Rules (Multiplication & Division)

• The answer should have the same number of significant figures as the measurement with the fewest significant figures.

Sig Figs Rules (Addition & Subtraction)

• The answer should have the same number of decimal places as the measurement with the fewest decimal places.

Density

• Density is a physical property that relates the mass of a substance to its volume.
• Density = mass/volume

Specific Gravity

• Ratio between density of the substance and density of water.

Volume Displacement

• Method to calculate the volume of an object by measuring the change in the volume of a liquid.

Conversions

• Method to change a value in one unit into another unit.

Percentages

• Part of the whole is given as the ratio of the part to whole expressed mathematically.

Temperature Conversions

• Converting between Fahrenheit, Celsius, and Kelvin scales.

Atoms: Nucleus, Electrons, Protons, Neutrons

• Nucleus: Central region of an atom, containing protons and neutrons.
• Electrons: Orbit the nucleus, negatively charged.
• Protons: Positively charged, found in the nucleus.
• Neutrons: Neutral, found in the nucleus.

Atomic Number

• Number of protons in an atom, defining the element.

Mass Number

• Sum of protons and neutrons in an atom.

Atomic Mass

• Weighted average mass of an atom of an element.

Isotopes

• Atoms of the same element that have the same number of protons but different numbers of neutrons.

Electron Configuration

• Arrangement of electrons in shells and orbitals.

Metals, Nonmetals, Metalloids

• Metals are typically shiny, good conductors of heat and electricity, malleable, ductile, and have high melting points.
• Nonmetals are typically not shiny, poor conductors of heat and electricity, brittle, and have low melting points.
• Metalloids exhibit properties of both metals and nonmetals.

Groups and Periods

• Elements in the periodic table are arranged in groups and periods, with similar properties grouped together.

Properties of Elements (Metals, Nonmetals, Noble Gases, etc.)

• Characteristics of different types of elements based on their location on the periodic table.

Atomic Size

• The size of atoms affects how reactive or inert an element is.

Atomic Radius

• Measure of the size of an atom.

Ionization Energy

• Energy needed to remove an electron from an atom.