Physical and Chemical Properties and Changes

Physical vs. Chemical Properties

• Physical properties are observed without changing the substance.

• Examples: color, melting point, boiling point, density, state.

• Chemical properties describe how a substance reacts or changes into a new substance.

• Examples: flammability, reactivity with acid, oxidizing ability.

Physical vs. Chemical Changes

• Physical changes do not alter the chemical makeup.

• Examples: melting, freezing, dissolving, cutting.

• Chemical changes result in new substances.

• Indicators of chemical change include color change, gas production, precipitate formation, and temperature change.

• Examples: rusting, burning, decomposition.

States of Matter (Solids, Liquids, Gases)

• Solids: have a fixed shape and volume, particles are tightly packed.

• Liquids: take the shape of their container, fixed volume, particles are loosely packed.

• Gases: fill their containers completely, variable shape and volume, particles are widely spaced.

• Compressibility: Solids are incompressible, liquids are slightly compressible, and gases are highly compressible.

Classifying Matter

• Pure substances have fixed compositions.

  • Examples: elements (e.g., oxygen, gold) and compounds (e.g., water, NaCl).

• Mixtures are physical combinations of substances.

  • Mixtures can be homogeneous (uniform, like saltwater) or heterogeneous (non-uniform, like salad).

Forms of Energy

• Kinetic energy is the energy of motion.

• Potential energy is stored energy due to position.

• Chemical energy is stored in chemical bonds.

• Thermal energy is related to temperature and molecular movement.

Laws of Thermodynamics

• Zeroth Law: If two systems are in thermal equilibrium with a third, they are in equilibrium with each other.

• First Law: Energy cannot be created or destroyed, only transferred.

• Second Law: Entropy (disorder) in an isolated system always increases.

• Third Law: As temperature approaches absolute zero, entropy approaches a constant.

Calorimetry

• Calorimetry is measuring heat transfer.

• The formula for heat transfer(q) = mass (m) * specific heat capacity (c) * temperature change (ΔT).

• Applications include determining the heat released or absorbed in reactions.

Explore the differences between physical and chemical properties and changes. This quiz will test your understanding of various states of matter and the characteristics that define them. Get ready to differentiate between how substances behave and transform under different conditions.