Key Concepts in Chemistry

Flashcards highlighting key terms and concepts from chemistry related to properties of water, mixtures, and acids and bases.

Hydrogen

A chemical element with the symbol H+.

Polarity

The property of having two opposite poles.

Polar Molecules

Molecules that have an unequal distribution of charges, such as water, which has a slightly negative end and two slightly positive ends.

Van der Waals Forces

Weak electrostatic attractions between molecules due to regions of opposite charge.

Hydrogen Bond

A weak attraction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom, considered a type of van der Waals force.

States of Matter

Water can exist in three different states: gas, liquid, and solid.

Freezing Point

The temperature at which a substance changes from the liquid state to the solid state.

Boiling Point

The temperature at which a liquid boils, specifically 212°F (100°C) for water.

Temperature

A quantitative measure of how hot or cold something is.

Adhesion

When water is attracted to other substances.

Cohesion

When water is attracted to water.

Mixture

A combination of two or more substances in which each retains its individual characteristics.

Homogeneous Mixture

A mixture with a uniform composition throughout.

Heterogeneous Mixture

A mixture where the components remain distinct.

Solution

A type of homogeneous mixture composed of a solvent and a solute.

Suspension

A type of heterogeneous mixture in which the particles settle out.

Colloid

A heterogeneous mixture in which the particles do not settle out.

Acids

Substances that release hydrogen ions (H+) when dissolved in water.

Bases

Substances that release hydroxide ions (OH-) when dissolved in water.

pH

The measure of the concentration of hydrogen ions (H+) in a solution.

Buffers

Mixtures that can react with acids or bases to keep the pH within a particular range.