FORMULAE FOR CONCENTRATION

Mass in volume ratios

Mass of a dissolved ingredient per volume amount of mixtures containing that ingredient

mEq / per volume

mEq of an electrolyte or salt per unit of volume of solutions containing that electrolyte or salt

Molality (m)

moles (mol)  of a solute/kg of a solvent containing that solute
(1 mol of solute per 1 kg of solvent is a 1 molal (1 m) solution)

Molarity (M)

mol of a solute/L of a solvent containing that solute
(1 mol of solute per 1 L of solution of that solute is a 1 molar (1 M) solution)

Normality (N)

1 Eq of solute per 1 L of solution of that solute is a 1 normal (1 N) solution.

normality formula

Molarity × largest valence ion of a compound)

what normality is?

Equivalents (Eq) of a solute/L of a solvent containing that solute

Parts per million (ppm)

Parts of a gas, liquid, or solid per 1 million part of another gas, liquid, or solid containing the first gas, liquid, or solid

% Volume in volume (% v/v)

mL of liquid per 100 mL of a solvent containing that liquid

% Weight in volume (% w/v)

g of a solute per 100 mL of a solvent containing that solute

% Weight in weight (% w/w)

g of a solute per 100 g of a mixture containing that solute

Ratio strength

1:R

1 part of an ingredient in R parts of a mixture containing that ingredien

1 in R

1 part of an ingredient in R parts of a mixture containing that ingredien

X:Y

X parts of one ingredient per Y parts of another ingredient in a mixture

R, X, and Y are whole numbers

ratio

express concentration as parts of the individual components or part of the components in the total mixture.

same units for numerator and denominator so they cancel out

what the unit part of weight

grams

what the unit part for milliliters

mL

molar ratio

ratio of the number of moles of one component in the reaction with the number of moles of another component in the reaction.

molar fraction

number of moles of a component as a fraction of the total number of moles.

Parts per million (ppm)

number of parts (g) per million parts of the total mixture.

units are mL for liquids or grams for solids.

what is Parts per million (ppm) used for?

generally used to express very low concentrations (e.g impurities such as metal ions).

concentration

express as the mass /units volume

percentage concentration

defined as the quantity of the substance in100 parts of the total quantity of the mixture

how can percentage be expressed?

expressed as % w/v, or % w/w or % v/v.

if density known?

% w/v can be converted to % w/w