Chemistry Quiz Notes PDF

Compound A substance made of two or more elements chemically bonded in a fixed ratio. Molecule A group of atoms bonded together; the smallest unit of a compound. Mass The amount of matter in an object, measured in grams or kilograms. Volume The space an object occupies, measured in lite...

Compound A substance made of two or more elements chemically bonded in a fixed ratio. Molecule A group of atoms bonded together; the smallest unit of a compound. Mass The amount of matter in an object, measured in grams or kilograms. Volume The space an object occupies, measured in liters (L) or cubic centimeters (cm³). Density Mass per unit of volume, calculated as Density = Mass ÷ Volume (g/cm³). Substance Matter with a uniform composition; can be an element or a compound. Element A pure substance made of one type of atom; cannot be broken down further. Atom The smallest unit of an element that keeps its chemical properties. Matter Anything that has mass and takes up space. New Terms for Quiz Part 2: Mixture Two or more substances physically combined; can be separated. Solid State of matter with a fixed shape and volume; particles vibrate in place. Liquid State with a fixed volume but no shape; particles can flow past each other. Gas State with no fixed shape or volume; particles move freely. Phase/State of Matter The physical form of matter: solid, liquid, gas, or plasma. Melting Point The temperature at which a solid becomes a liquid. Boiling Point The temperature at which a liquid becomes a gas. Physical Properties What is a physical property? A characteristic that can be observed without changing the substance, like color or density. What determines physical properties? The type of particles, their arrangement, and their interactions. Size-dependent vs. size-independent properties: Size-dependent: Changes with the amount of matter (e.g., mass, volume). Size-independent: Stays constant (e.g., density, melting point). How is mass different from weight? Mass: The amount of matter, constant everywhere. Weight: Depends on gravity and varies with location. Density What two properties are needed to calculate density? Mass and volume. Why do objects sink or float? Sink: Density is greater than water (1 g/cm³). Float: Density is less than water. States/Phases of Matter What happens at the melting point? Particles gain energy, move faster, and change from solid to liquid. What happens at the boiling point? Particles gain enough energy to become a gas. How do phase changes affect mass, volume, and density? Mass: Stays the same (Law of Conservation of Mass). Volume: Changes as particles spread out or pack together. Density: Changes due to changes in volume. Conservation of Mass/Matter Law of Conservation of Mass Matter cannot be created or destroyed during a chemical or physical change. Example: In an Alka-Seltzer reaction, gas is released, but the total mass of the system stays the same.