Chapter 3: Composition of Substances and Solutions

Flashcards covering key vocabulary and concepts from the lecture notes on composition of substances and solutions.

Formula Mass

The sum of the atomic masses of all the atoms in its chemical formula.

Molecular Mass

The formula mass of a covalent substance.

Mole

A unit that helps us carry out calculations with very large numbers. The SI abbreviation is mol.

Avogadro’s Number

A number equal to 6.022 x 1023.

Molar Mass

The mass (g) of 1 mole of atoms or molecules, expressed in grams per mole (g/mol).

Percent Composition

The percentage by mass of each element in a compound.

% element A

The percentage by mass of each element in a compound (mass of element A / mass of compound) x 100.

Empirical Formula

A compound's simplest whole number ratio of atoms in a compound.

Molecular Formula

A compound's actual number of atoms of each element in a molecule.

Solution

A homogeneous mixture with uniform composition and properties throughout its entire volume.

Concentration

The relative amount of a given solution component.

Solvent

The component present in the largest amount in a solution.

Solute

The component(s) present in smaller amounts than the solvent in a solution.

Aqueous Solution

A solution in which water is the solvent.

Concentrated Solution

Relatively high concentration of solute.

Dilute Solution

Relatively low concentration of solute.

Molarity (M)

The number of moles of solute in exactly 1 liter (L) of the solution.

Dilution

Decreasing the concentration of a solution by adding a solvent.

Mass percentage

mass of solute divided by mass of solution times 100.

Volume percentage

volume of solute divided by volume of solution times 100.

Mass-Volume percentage

mass of solute divided by volume of solution times 100.

ppm

mass solute/mass of solution x 10^6

ppb

mass solute/mass of solution x 10^9