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What distinguishes chemical bonds from intermolecular forces in terms of their strength and function?
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Chemical bonds are strong forces holding atoms together within a molecule, while intermolecular forces are weaker attractions between molecules causing aggregation.
What information can be gleaned from a phase diagram regarding the states of a substance?
A phase diagram shows which phase is stable at various temperatures and pressures, indicating regions of fusion, sublimation, vaporization, the triple point, and the critical point.
How does capillary action occur and what forces are involved in this process?
Capillary action occurs when a liquid rises in a narrow tube due to cohesive forces within the liquid and adhesive forces between the liquid and the tube's surface.
Explain the relationship between viscosity and temperature for a liquid with strong intermolecular forces.
In a liquid with strong intermolecular forces, viscosity decreases with increasing temperature due to the reduction in intermolecular interactions.
How does vapor pressure relate to intermolecular forces and what effect does it have on boiling point?
Vapor pressure is lower in substances with stronger intermolecular forces, leading to a higher boiling point.
What is the significance of the triple point in a phase diagram?
The triple point is where all three phases (solid, liquid, gas) co-exist in equilibrium.
Describe the roles of heat of fusion and heat of vaporization in phase changes.
Heat of fusion is the energy required for a substance to change from solid to liquid, while heat of vaporization is the energy needed to change from liquid to gas.
What is the role of vapor pressure in determining whether a liquid will evaporate at a given temperature?
Vapor pressure must equal atmospheric pressure for a liquid to evaporate at a given temperature; stronger intermolecular forces reduce vapor pressure, making evaporation less likely.
How can you determine the presence of hydrogen bonds in a molecular substance?
Presence of hydrogen bonds is indicated by a hydrogen atom bonded to F, O, or N within the molecule, leading to strong intermolecular attractions.
What are London dispersion forces and in what types of substances are they most prevalent?
London dispersion forces are temporary induced dipole interactions present in nonpolar substances, most prevalent in substances with larger molecular size and greater polarizability.
How do dipole-dipole forces arise and how does their strength vary?
Dipole-dipole forces occur between polar molecules with permanent dipoles, and their strength increases with increasing polarity.
Describe an exothermic phase change and provide an example.
An exothermic phase change releases energy as it occurs, such as freezing, condensation, or deposition.
What characterizes a substance as a supercritical fluid beyond its critical point?
A supercritical fluid, beyond its critical point, cannot be distinguished as either a liquid or a gas and exhibits properties of both states.
Why do substances with stronger intermolecular forces exhibit higher surface tension?
Stronger intermolecular forces increase the energy required to expand a liquid's surface area, resulting in higher surface tension.
Explain why hydrogen bonds, despite not being true bonds, are considered strong intermolecular forces.
Hydrogen bonds are significant because they involve a strong attraction between a polarized hydrogen atom and a highly electronegative atom (F, O, N) in another molecule.
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