Classifying Matter, Physical & Chemical Properties (9th Grade)

What is Matter?

  • ____ is anything that has mass and occupies space. It exists as a solid, liquid, or gas.

Particle Model of Matter

  • All matter is made of tiny particles.

  • Each pure substance has unique particles.

  • Higher temperature means faster particle movement.

  • Particles attract each other and have spaces between them, always moving.

How do we change from one state (or phase) to another?

  • Matter changes phase with temperature or pressure changes.

What do we see when temperature Increases?

  • Melting: solid to liquid

  • Boiling and Evaporation: liquid to gas

  • Increased temperature changes state.

Boiling Points and Melting Points

  • Boiling Points (examples): Water: 100∘C100^\circ\mathrm{C}, Table Salt: 1413∘C1413^\circ\mathrm{C}

  • Melting Points (examples): Ice: 0∘C0^\circ\mathrm{C}, Table Salt: 801∘C801^\circ\mathrm{C}

What do we see when temperature decreases?

  • Condensation: gas to liquid

  • Freezing: liquid to solid

  • Decreased temperature changes state.

Phase/State Change Terms

  • Melting: Solid to Liquid

  • Evaporation: Liquid to Gas

  • Condensation: Gas to Liquid

  • Freezing: Liquid to Solid

  • Sublimation: Solid directly to a _

  • Deposition: Gas directly to Solid

What is happening to the particles?

  • When solid melts, particles move faster and spread out.

  • When liquid boils, particles move even faster, breaking free to become gas.

Atoms & Molecules

  • Atoms: smallest unit of matter retaining element's chemical properties.

  • Molecules: two or more atoms forming the smallest unit of a pure substance, retaining its composition and chemical properties.

Pure Substances

  • ____ substances contain only ONE type of particle and can exist in all three phases.

  • Categories: Elements & Compounds.

  • All Matter \u2192 Pure Substances \u2192 Elements or Compounds.

What is an Element?

  • Elements are collections of the same atoms, found on the periodic table.

Element Examples

  • Plutonium, noble gases, nitrogen.

What is a Compound?

  • ____ consist of two or more elements chemically bonded in a fixed ratio.

Common Compound Examples

  • Water, carbon dioxide, sodium chloride.

So, what’s the difference between an element and a compound?

  • Element = SAME type of atoms.

  • Compound = DIFFERENT elements in fixed ratios.

Practice: categorize as either a mixture, a compound or an element

  • Pop (water, sugar, carbon dioxide) \u2192 mixture

  • Graphite (carbon) \u2192 element

  • Carbon dioxide (carbon, oxygen) \u2192 compound

Practice (Answer Key) – Categorize practice items

  • a) mixture

  • b) element

  • c) compound

What is a Mixture?

  • Mixtures contain two or more pure substances mixed together.

  • They are either (also called Solutions) or Heterogeneous (also called mechanical mixtures).

  • All Matter \u2192 Mixtures or Pure Substances; Mixtures can be Homogeneous or Heterogeneous.

Homogeneous vs Heterogeneous

  • Homogeneous: Difficult to see parts; uniform.

  • Heterogeneous: Able to see parts; not uniform.

Other Homogeneous Mixtures

  • Colloids: cloudy mixtures with small, distributed particles that do not settle (e.g., milk).

Suspensions (a type of heterogeneous mixture)

  • Suspensions: cloudy mixtures with tiny particles held within another, separable by filtering, will settle (e.g., tomato sauce).

Check for Understanding! – Are these mixtures or pure substances?

  • Iron (Fe) \u2192 element (pure substance)

  • Glucose (C6H12O6) \u2192 compound (pure substance)

  • Chocolate chip cookies \u2192 mixture

  • Milk \u2192 mixture

Physical & Chemical Properties of Matter

  • Physical Properties: Observable/measurable without forming a new substance.

Qualitative vs Quantitative Properties

  • Qualitative: Color, texture, taste, smell, state, crystal structure, malleability, ductility.

  • Quantitative: Melting point, boiling point, density, viscosity, solubility, electrical/heat conductivity.

Chemical Properties

  • Describe how a substance reacts with another substance.

  • WILL CHANGE the substance, creating a new one (e.g., reaction with air, toxicity, stability).

Check in: Physical and chemical properties and changes

  • Properties describe substances; changes are results of alterations.

  • Examples: Malleability (physical property); Melting (physical change); Digestion (chemical change); Flammability (chemical property).

Physical & Chemical Changes

  • Physical change: state altered, chemical composition unchanged (e.g., ice cream melting).

  • Chemical change: substances react, new substance formed (e.g., stomach acid digesting food).

What is a Physical Change?

  • Matter changes state, physical appearance changes, but composition does not.

What is a Chemical Change?

  • May include: Change in colour/odour, formation of solid/gas, release/absorption of heat.