Lecture 2: Electronegativity, Hydrogen Bonds, and Water

Vocabulary flashcards covering key terms related to electronegativity, bonds, hydrogen bonding, and water properties from Lecture 2.

Chemical reaction

Process of breaking and forming chemical bonds, converting reactants into products.

Cohesion

Hydrogen bonds holding water molecules together.

Electronegativity

Atom’s attraction for electrons in a covalent bond.

Evaporative cooling

Cooling of a liquid’s surface as molecules with higher energy evaporate.

Heat of vaporization

Heat required to convert 1 g of liquid into gas.

Hydration shell

Sphere of water molecules surrounding an ion or polar molecule in solution.

Hydrogen bond

Weak bond between a hydrogen covalently bonded to an electronegative atom and another electronegative atom.

Hydrophilic

Substance with affinity for water (polar/ionic).

Hydrophobic

Substance that repels water (nonpolar).

Molecular shape

Determined by positions of atom orbitals and repulsion among electrons.

Nonpolar covalent bond

Equal sharing of electrons between atoms.

Polar covalent bond

Unequal sharing of electrons between atoms, creating partial charges.

Photosynthesis

Process where CO2 and H2O are converted into glucose and oxygen using solar energy.

Polarity of water

Water is a polar molecule with unequal distribution of charge, enabling hydrogen bonding.

Specific heat

Amount of heat needed to raise or lower 1 g of a substance by 1°C.

Van der Waals interactions

Weak intermolecular forces due to uneven electron distribution.

Expansion upon freezing

Ice is less dense than liquid water, causing water to expand when it freezes.

Water solvent properties

Water’s ability to dissolve many substances due to its polarity.