Engineering English
Activity Coefficient
Chemical Engineering · Last updated: July 30, 2026 · How this entry was written
Definition: The activity coefficient accounts for deviations from ideal behavior in liquid mixtures. It is used to modify concentration in thermodynamic equations.
Example in context
“Using the NRTL model, we calculated the activity coefficients for the ethanol-water system at azeotropic composition.”
“NRTL modelini kullanarak, azeotropik bileşimde etanol-su sistemi için aktivite katsayılarını hesapladık.”
Where engineers use it
Activity coefficients are essential in liquid-liquid extraction, distillation of non-ideal mixtures, and electrolyte thermodynamics. Engineers use models like NRTL, UNIQUAC, or Wilson to predict phase splitting.
Practice: can you use “Activity Coefficient” at work?
You are tasked with extracting acetic acid from water using ethyl acetate. The system exhibits non-ideality. Use activity coefficient models to estimate the distribution coefficient.
Show a model answer
“Activity coefficients are necessary when modeling non-ideal liquid mixtures.”
“Activity Coefficient” in 21 languages
| English | Activity Coefficient |
|---|---|
| Turkish | aktivite katsayısı |
| French | coefficient d'activité |
| German | Aktivitätskoeffizient |
| Spanish | coeficiente de actividad |
| Chinese | 活度系数 |
| Arabic | معامل النشاط |
| Portuguese | coeficiente de atividade |
| Russian | коэффициент активности |
| Japanese | 活量係数 |
| Italian | coefficiente di attività |
| Vietnamese | hệ số hoạt độ |
| Hindi | सक्रियता गुणांक |
| Thai | สัมประสิทธิ์กิจกรรม |
| Indonesian | koefisien aktivitas |
| Korean | 활동도 계수 |
| Bengali | সক্রিয়তা সহগ |
| Dutch | activiteitscoëfficiënt |
| Swedish | aktivitetskoefficient |
| Finnish | aktiivisuuskerroin |
| Ukrainian | коефіцієнт активності |
Frequently asked questions
What does Activity Coefficient mean in engineering?
The activity coefficient accounts for deviations from ideal behavior in liquid mixtures. It is used to modify concentration in thermodynamic equations. In Chemical Engineering, the term carries a usage-frequency rating of 10/10 in the Engineering English library.
How do you pronounce Activity Coefficient?
Activity Coefficient is pronounced /ækˈtɪvɪti ˌkoʊɪˈfɪʃənt/ (IPA). The Engineering English app plays audio for the term and checks your pronunciation with speech recognition.
How is Activity Coefficient used in a sentence?
Example from an engineering context: “Using the NRTL model, we calculated the activity coefficients for the ethanol-water system at azeotropic composition.”
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