Chemical Substances and Mixtures Quiz

Definition: A chemical substance is a form of matter that has a specific chemical composition and distinct properties.

Definition: A combination of two or more substances where each retains its individual properties.
Types:
- Homogeneous Mixtures: Uniform composition throughout (e.g., saltwater).
- Heterogeneous Mixtures: Non-uniform composition; distinct phases can be seen (e.g., salad, sand and iron filings).
Separation Methods:
- Filtration
- Distillation
- Chromatography

Definition: A substance formed when two or more elements chemically bond together.
Characteristics:
- Fixed composition; defined ratio of elements.
- Properties differ from the individual elements (e.g., water vs. hydrogen and oxygen).
Types:
- Ionic Compounds: Formed by ionic bonds between metals and nonmetals (e.g., sodium chloride).
- Covalent Compounds: Formed by covalent bonds between nonmetals (e.g., carbon dioxide).
Chemical Formulas: Represent the ratio and types of atoms present (e.g., H2O for water).

Definition: Pure substances that cannot be broken down into simpler substances by chemical means.
Characteristics:
- Consist of only one type of atom.
- Represented by symbols (e.g., H for hydrogen, O for oxygen).
Classification:
- Metals: Good conductors, malleable, ductile (e.g., iron, copper).
- Nonmetals: Poor conductors, brittle in solid form (e.g., sulfur, nitrogen).
- Metalloids: Have properties of both metals and nonmetals (e.g., silicon, boron).
Periodic Table: Organized by atomic number; groups elements with similar properties.

A chemical substance has a specific chemical composition and distinct properties that define its behavior and interactions.

A mixture consists of two or more substances combined, where each substance retains its individual properties.
Homogeneous Mixtures: Have a uniform composition throughout, such as saltwater, where the salt is evenly dissolved.
Heterogeneous Mixtures: Display non-uniform composition with visible distinct phases, such as a salad or a mixture of sand and iron filings.
Separation Methods: Techniques to isolate components in mixtures include:
- Filtration: Uses a barrier to separate solid particles from liquids.
- Distillation: Relies on differences in boiling points to separate substances.
- Chromatography: Separates components based on their movement through a medium.

Compounds form when two or more elements chemically bond together, resulting in a substance with a fixed composition and defined ratio of elements.
The properties of compounds differ from those of the individual elements (e.g., water exhibits different properties compared to hydrogen and oxygen).
Types of Compounds:
- Ionic Compounds: Result from ionic bonds between metals and nonmetals (e.g., sodium chloride).
- Covalent Compounds: Result from covalent bonds between nonmetals (e.g., carbon dioxide).
Chemical Formulas: Represent the ratio and types of atoms in a compound (e.g., H2O signifies two hydrogen atoms and one oxygen atom).

Elements are pure substances that cannot be chemically broken down into simpler substances and consist of only one type of atom.
Each element is represented by a unique symbol (e.g., H for hydrogen, O for oxygen).
Classification of Elements:
- Metals: Good conductors of heat and electricity, malleable, and ductile (e.g., iron, copper).
- Nonmetals: Poor conductors, generally brittle in solid form (e.g., sulfur, nitrogen).
- Metalloids: Display properties of both metals and nonmetals (e.g., silicon, boron).
The Periodic Table organizes elements by atomic number and groups them based on similar chemical properties.

Solutions are uniform mixtures made of solute and solvent, such as saltwater or sugar dissolved in water.
Alloys consist of uniform mixtures of metals, including bronze and brass.
Gases represent homogeneous mixtures, evident in the atmosphere where air is a mix of various gases.
Colloids feature dispersed particles that remain suspended and do not settle, examples include milk and fog.
Syrups are homogeneous mixes of sugar and water, maintaining uniform consistency.

Uniform composition means that every part of the mixture has the same ratio of constituents.
These mixtures exist in a single phase, which can be solid, liquid, or gas.
The individual components of homogeneous mixtures cannot be separated easily by physical methods.
Stability is a key trait; the mixture maintains its uniformity over time without separation.
Appearance remains consistent throughout the mixture, no matter the sample size observed.

Composition differs: homogeneous mixtures are uniform, while heterogeneous mixtures show variability with distinguishable components.
Visibility of components in homogeneous mixtures is low; they are indistinguishable, contrasting with heterogeneous mixtures where components are easily seen and identified.
Separation methods required for homogeneous mixtures are complex and usually rely on chemical processes, unlike heterogeneous mixtures, which can be simply separated using physical methods like filtration and decantation.
Examples include saltwater and air for homogeneous mixtures, and salad and soil for heterogeneous mixtures.
Homogeneous mixtures exist in a single phase while heterogeneous mixtures can show multiple phases.