Chemistry Chapter 10 Flashcards

Questions and Answers

What are intramolecular forces?

Interaction between atoms within a molecule.

What are intermolecular forces?

Interactions between molecules/atoms.

Which are stronger, intermolecular forces or intramolecular forces?

Intramolecular forces are stronger.

What influences water's physical properties (including its boiling point and melting point)?

Its polarity. Signup and view all the answers

How do the attractive forces of a molecule influence its physical properties?

Stronger attractive forces lead to higher melting and boiling points. Signup and view all the answers

What is the relationship between energy required to separate particles and boiling point?

The greater the amount of energy required to separate the particles, the higher the boiling point. Signup and view all the answers

What is an induced dipole?

The separation of charge produced in an atom or molecule by a momentary uneven distribution of electrons. Signup and view all the answers

Why are the partial charges in temporary dipoles in molecules more likely to be distributed over greater distances than in single atoms?

Because atomic nuclei and electron clouds shared by groups of atoms interact with neighboring atoms or molecules. Signup and view all the answers

What is lattice energy?

Lattice energy is related to how much energy it takes to separate ions in an ionic solid. Signup and view all the answers

Larger lattice energies typically correspond to what?

High melting points. Signup and view all the answers

What is a dispersion force?

An intermolecular force between nonpolar molecules caused by temporary dipoles. Signup and view all the answers

Why do the strength of dispersion forces increase as the number of electrons in atoms and molecules increase?

Greater polarizability leads to stronger temporary dipoles and stronger intermolecular interactions. Signup and view all the answers

What is polarizability?

The relative ease with which the electron cloud in a molecule, ion, or atom can be distorted, inducing a temporary dipole. Signup and view all the answers

Why do larger molecules have higher boiling points?

They have more surface area to interact with each other, increasing chances for dispersion forces. Signup and view all the answers

What are ion-dipole interactions?

An attractive force between an ion and a molecule that has a permanent dipole moment. Signup and view all the answers

Why can a salt such as NaCl dissolve in water?

Ion-dipole interactions must overcome the electrostatic interactions between the ions themselves. Signup and view all the answers

Study Notes

Intermolecular and Intramolecular Forces

Intramolecular forces refer to interactions within a molecule between its atoms.
Intermolecular forces are interactions that occur between different molecules or atoms.
Intramolecular forces are significantly stronger (100-1000 kJ/mol) compared to intermolecular forces (1-100 kJ/mol).

Properties of Water

Water's unique physical properties, such as its boiling and melting points, are influenced by its polarity.
Strong attractive forces in solids require more energy to overcome, resulting in higher melting and boiling points, indicating solidity at room temperature.
Substances with weaker interactions tend to be liquids, while those with very weak interactions are likely gases.

Boiling Point and Energy

Higher energies required to separate particles correlate with higher boiling points.

Dipoles and Interactions

An induced dipole results from temporary uneven electron distribution in atoms or molecules, leading to charge separation.
Temporary dipoles can extend further in molecules due to interactions between atomic nuclei and shared electron clouds.

Lattice Energy

Lattice energy represents the energy needed to separate ions in an ionic solid. Larger (more negative) lattice energy indicates stronger ionic interactions.
High melting points in ionic compounds are typically associated with larger lattice energies.

Dispersion Forces

Dispersion forces are intermolecular forces that act between nonpolar molecules, driven by temporary dipoles.
All atoms and molecules experience London dispersion forces; larger electron clouds lead to easier polarization and stronger intermolecular interactions.
Increased polarizability results in stronger temporary dipoles and hence stronger dispersion forces.

Molecular Size and Boiling Points

Larger molecules possess more surface area, increasing the likelihood of interactions through dispersion forces, leading to higher boiling points.

Ion-Dipole Interactions

Ion-dipole interactions occur between an ion and a molecule with a permanent dipole, representing another form of intermolecular force.

Dissolution of Salt in Water

The ability of salts like NaCl to dissolve in water is due to ion-dipole interactions overcoming the electrostatic forces holding the ions together.
When dissolved, the ions become surrounded by water molecules, forming a hydration sphere.

Sphere of Hydration

Water molecules in the hydration sphere orient based on the charge of the ion; oxygen atoms face cations and hydrogen atoms face anions, with the extent of orientation depending on the size of the ion.

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Description

Test your understanding of intermolecular and intramolecular forces with this set of flashcards from Chemistry Chapter 10. Learn key definitions and concepts that highlight the strengths and differences between these types of forces, particularly in relation to the unique properties of water.