molality: meaning, definition, pronunciation and examples
C2 (Proficient user)Technical/Academic
Quick answer
What does “molality” mean?
A measure of the concentration of a solute in a solution, expressed as moles of solute per kilogram of solvent.
Audio
Pronunciation
Definition
Meaning and Definition
A measure of the concentration of a solute in a solution, expressed as moles of solute per kilogram of solvent.
A physical chemistry property used to quantify solution concentration that remains unaffected by changes in temperature and pressure, unlike molarity, due to its mass-based definition.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage; the term is strictly technical.
Connotations
Purely scientific, with no regional connotative differences.
Frequency
Used exclusively in scientific and engineering contexts in both regions.
Grammar
How to Use “molality” in a Sentence
The molality of X is YCalculate the molality of XX has a molality of YVocabulary
Collocations
Examples
Examples of “molality” in a Sentence
adjective
British English
- The molal concentration was crucial for the experiment.
American English
- Molal quantities are standard in this thermodynamic model.
Usage
Meaning in Context
Business
Not applicable in standard business contexts.
Academic
Frequently used in chemistry, chemical engineering, and materials science textbooks and research papers, especially in sections on solution properties and thermodynamics.
Everyday
Virtually never used in everyday conversation.
Technical
Essential in laboratory protocols, chemical process design, and analytical chemistry for precise concentration specification.
Vocabulary
Synonyms of “molality”
Neutral
Weak
Vocabulary
Antonyms of “molality”
Watch out
Common Mistakes When Using “molality”
- Confusing molality with molarity (moles per litre).
- Using 'molality' to refer to concentration in general, rather than its specific definition.
- Misspelling as 'molarity' or 'mollality'.
FAQ
Frequently Asked Questions
Molality (m) is moles of solute per kilogram of solvent. Molarity (M) is moles of solute per litre of solution. Molality is temperature-independent; molarity is not.
Use molality for precise physical chemistry work, especially involving colligative properties (like freezing point depression) or when temperature varies significantly, as the mass of solvent does not change with temperature.
The SI derived unit for molality is mol/kg (moles per kilogram).
Yes, molality is particularly useful for concentrated solutions or where precise temperature-independent data is needed, as volume-based measures like molarity become less reliable at high concentrations or varying temperatures.
A measure of the concentration of a solute in a solution, expressed as moles of solute per kilogram of solvent.
Molality is usually technical/academic in register.
Molality: in British English it is pronounced /məʊˈlæl.ɪ.ti/, and in American English it is pronounced /moʊˈlæl.ə.t̬i/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think 'MOLality = MOLes per kilogram, Like mass stays constant' to remember it's based on solvent mass.
Conceptual Metaphor
N/A (Highly technical term).
Practice
Quiz
What is the primary advantage of using molality over molarity in thermodynamic calculations?