AP Chem

• What is the title of the topic discussed in the study material?

  Properties of Solids
• Who is the author of the study material on properties of solids?

  Emily Miller
• What is the learning objective of the topic on properties of solids?


  Explain the relationship among macroscopic properties, particulate-level structure, and particle interactions.
• What determines many properties of liquids and solids?

  The strengths and types of intermolecular forces present.
• How are vapor pressure and boiling point related to intermolecular interactions?


  They are directly related to the strength of intermolecular interactions.
• Why do melting points correlate with interaction strength?


  Because melting involves rearranging interactions rather than breaking them.
• What is the significance of particulate-level representations in understanding solids?


  They help communicate how intermolecular interactions establish macroscopic properties.
• What are the four basic types of solids mentioned in the study material?

  Ionic solids, covalent network solids, molecular solids, metallic solids.
• What characterizes ionic solids in terms of their lattice structure?


  Ionic solids have ions at the points of the lattice.
• Why do ionic solids tend to have low vapor pressures and high melting points?


  Due to strong interactions between ions.
• What is the attraction between positive and negative ions in ionic solids called?


  Electrostatic attraction.
• According to Coulomb’s Law, what factors affect the strength of attraction between ions?


  Smaller ions and/or ions with higher charges result in stronger attractions.
• Why are ionic solids generally brittle?


  Due to the repulsion of like charges when one layer slides across another layer.
• When do ionic solids conduct electricity?


  When the ions are mobile, such as when melted or dissolved in a solvent.
• What type of atoms form covalent network solids?


  Nonmetals.
• What is a characteristic of covalent network solids in terms of their structure?


  They form a three-dimensional network or layers of two-dimensional networks.
• Why do covalent network solids have high melting points?


  Because covalent bonds must be broken to melt them, and these bonds are strong.
• What is the difference in hardness between diamond and graphite?


  Diamond is hard due to its three-dimensional network, while graphite is soft because layers can slide past each other.
• What is silica (SiO2) composed of?


  Many SiO4 molecules in a tetrahedral shape.
• What is the structure of glass in terms of its atomic arrangement?


  Glass is an amorphous solid with considerable disorder among its components.
• What are the properties of molecular solids?


  They are composed of distinct units of covalently-bonded molecules attracted by weak intermolecular forces.
• Why do molecular solids generally have low melting points?


  Because of the relatively weak intermolecular forces present between the molecules.
• Why do molecular solids not conduct electricity?


  Because their valence electrons are tightly held within covalent bonds.
• What is an example of a molecular solid held together by hydrogen bonds?


  Ice (H2O).
• What is an example of a molecular solid held together by London Dispersion forces?


  Dry ice (CO2).
• What characterizes metallic solids in terms of their atomic structure?


  They consist of metallic crystals with spherical metal atoms packed together.
• What is a metallic bond?


  A close packed lattice of positive atoms/ions surrounded by a sea of moving electrons.
• Why are metallic solids good conductors of heat and electricity?


  Due to the movement of free electrons.
• What allows metals to be malleable and ductile?


  The ease with which metal atoms/ions can rearrange their structure.
• What is the difference between substitutional and interstitial alloys?


  Substitutional alloys have similar-sized atoms substituting for each other, while interstitial alloys have smaller atoms filling spaces between larger atoms.
• What is an example of a substitutional alloy?


  14k gold (Ag atoms replace some Au atoms).
• What is an example of an interstitial alloy?


  Steel (C atoms fit between Fe atoms).
• How do noncovalent interactions affect large biomolecules or polymers?


  They dictate the shape and functionality of the molecules.
• What forms the secondary structure of a biomolecule?


  Attractions between different regions of the same large biomolecule through hydrogen bonding.
• What is the general order of increasing strength of interactions in solids?

  Molecular solids < ionic solids ≈ metallic solids < covalent solids.
• What type of solid is CO2 and what is its melting point?


  CO2 is a molecular solid and melts at -78°C.
• What type of solid is SiO2 and what is its melting point?


  SiO2 is a covalent network solid and melts at 1,650°C.
• Why does CO2 have a lower melting point than SiO2?


  CO2 is a molecular solid with weak intermolecular forces, while SiO2 is a covalent network solid requiring strong covalent bonds to be broken.
• What is the relationship between the type of solid and its melting point?


  The type of solid determines the strength of interactions, which influences the melting point.
• What is the role of noncovalent interactions in biomolecules?


  They influence the shape and properties of large biomolecules and polymers.