Chemistry Basics and Measurements

Chemistry Definition

• Chemistry studies the composition, structure, properties, and reactions of matter

Matter & Non-Matter

• Matter has mass and takes up space
• Non-matter lacks mass and does not occupy space

SI Units of Measurement

• Length: meter (m)
• Mass: kilogram (kg)
• Time: second (s)
• Temperature: Kelvin (K)
• Amount of substance: mole (mol)
• Electric current: ampere (A)
• Luminous intensity: candela (cd)

SI/Metric Unit Prefixes

• Kilo (k): 1000
• Hecto (h): 100
• Deka (da): 10
• Deci (d): 0.1
• Centi (c): 0.01
• Milli (m): 0.001
• Micro (µ): 0.000001
• Nano (n): 0.000000001

Scientific Notation

• Expressing very large or very small numbers using powers of 10

Density & Calculations

• Density: mass per unit volume
• Formula: Density = Mass/Volume

Dimensional Analysis

• Converting between different units using conversion factors

Temperature Conversions

• Celsius to Fahrenheit: °F = (°C × 9/5) + 32
• Fahrenheit to Celsius: °C = (°F - 32) × 5/9
• Kelvin to Celsius: K = °C + 273.15
• Celsius to Kelvin: °C = K - 273.15

Matter Classifications

• Pure substances: elements and compounds
• Mixtures: homogeneous and heterogeneous

Homogeneous vs. Heterogeneous Mixtures

• Homogeneous: uniform composition
• Heterogeneous: non-uniform composition

States of Matter

• Solid: fixed shape and volume
• Liquid: fixed volume, but takes the shape of its container
• Gas: no fixed shape or volume, expands to fill its container

Phase Changes

• Solid to liquid: melting
• Liquid to solid: freezing
• Liquid to gas: vaporization
• Gas to liquid: condensation
• Solid to gas: sublimation
• Gas to solid: deposition

Physical and Chemical Changes

• Physical change: alters the form or appearance of a substance, but not its chemical composition
• Chemical change: results in the formation of new substances with different chemical properties

Physical and Chemical Properties

• Physical property: can be observed without changing the substance's composition
• Chemical property: describes how a substance reacts with other substances

Atomic Structure

• Composed of protons, neutrons, and electrons
• Protons: positive charge, located in the nucleus
• Neutrons: no charge, located in the nucleus
• Electrons: negative charge, located in the electron cloud surrounding the nucleus

Atomic Number

• Number of protons in an atom's nucleus, defining the element

Chemical Symbols

• One or two letters representing an element

Isotopes

• Atoms of the same element with different numbers of neutrons
• Same atomic number, but different mass numbers

Average Atomic Mass

• Weighted average of the masses of all naturally occurring isotopes of an element

Ions

• Atoms that have gained or lost electrons
• Cations: positively charged ions
• Anions: negatively charged ions

Polyatomic Ions

• Groups of atoms with an overall charge

Ionic Compounds

• Formed by the electrostatic attraction between oppositely charged ions

Molecular Compounds

• Formed by the sharing of electrons between atoms

Mole & Avogadro's Number

• Mole: a unit of amount of substance
• Avogadro's number: 6.022 × 10^23 particles per mole

Atomic Weight, Molecular Weight, & Molar Mass

• Atomic weight: mass of one atom of an element
• Molecular weight: mass of one molecule of a compound
• Molar mass: mass of one mole of a substance

Percent Composition

• Percentage by mass of each element in a compound

Empirical & Molecular Formulas

• Empirical formula: simplest whole-number ratio of atoms in a compound
• Molecular formula: actual number of atoms of each element in a molecule

Finding Empirical & Molecular Formulas

• Empirical formula from percent composition: convert percentage to mass, then to moles, and find the simplest whole-number ratio of moles
• Molecular formula from empirical formula: calculate the molar mass of the empirical formula, and divide the molar mass of the compound by the molar mass of the empirical formula to determine the multiplier for the empirical formula

Practice Problems

• Chapter 1 (Page 50): 9, 11, 13, 19, 25, 29, 39, 45, 57, 65, 67, 75, 81, 87, 89, 93, 95, 97
• Chapter 2 (Page 107): 7, 19, 25, 29, 33, 39, 41, 47
• Chapter 3 (Page 151): 1, 5, 9, 13, 17, 19, 25, 27, 31, 39, 43

Test your knowledge on fundamental chemistry concepts including matter, SI units, and density calculations. This quiz will also cover scientific notation and temperature conversions, helping you solidify your understanding of essential measurement principles in chemistry.