Chemistry Chapter on Matter Changes

Types of Changes of Matter

• Physical Change: No change in composition; alterations in appearance or form, such as vaporization and pulverization.
• Chemical Change: Involves a transformation that alters composition, resulting in new substances; examples include combustion and corrosion.

States of Matter

• Primary states: Solid, Liquid, Gas.
• Other states include Plasma, Bose–Einstein Condensate, and Fermionic Condensate.
• Matter primarily exists as solid, liquid, or gas under normal conditions.

Important Chemical Quantities

• Mass: Amount of matter in a body, measured in grams (g), kilograms (kg), pounds (lbm), and milligrams (mg).
• Volume: Space occupied by matter, expressed in cubic centimeters (cm³), milliliters (mL), liters (L), and cubic meters (m³).

Atomic Weight and Molecular Weight

• Atomic Weight (AW): Indicates mass of atoms; values found in the Periodic Table (e.g., H = 1, C = 12).
• Molecular Weight (MW): Total mass of a compound's molecules, calculated using the atomic weights of its constituents.

Calculating Molecular Weights

• Count elements based on formula subscripts.
• Sum the atomic weights of each element present in the compound.

Density and Specific Gravity

• Density (ρ): Mass per unit volume of a substance.
• Specific Gravity (SG): Ratio of a substance's density to the density of water.
• Formulas:
  • Density: ( \text{density} = \frac{\text{mass}}{\text{volume}} )
  • Specific Gravity: ( SG = \frac{\text{density of substance}}{\text{density of water}} )

Temperature

• A measure of hotness or coldness, with units such as Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (R).
• Absolute Zero is the theoretical temperature where particle motion ceases.

Pressure

• Definition: Force exerted per unit area.
• Common units include Pascal (Pa), atmosphere (atm), millimeters of mercury (mmHg), and pound per square inch (psi).

Mole Concept

• Mole (n): Represents quantity of particles in a sample, measured in moles (mol).
• Conditions:
  • 1 mol = ( 6.022 \times 10^{23} ) particles.
  • Mass in grams is numerically equal to Atomic Weight for elements and Molecular Weight for compounds.

Properties Classification

• Extensive Properties: Depend on amount (e.g., length, mass, volume).
• Intensive Properties: Independent of amount (e.g., density, color, boiling point, temperature, melting point).