Applied Chemistry – thermodynamics, fire safety, computing
ChemistryApplied & Practical ChemistryAges 15–16
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Sign in to playThree applied-chemistry topics in one sim, selected with the topic parameter. Chemical thermodynamics: change the temperature to see at what point ΔG = ΔH − TΔS for the lime-roasting reaction CaCO₃ → CaO + CO₂ changes sign and the reaction becomes spontaneous. Chemistry in fire and explosion prevention: the fire triangle and the explosive concentration range of methane, LPG and hydrogen — click the ignition source to see whether a fire or explosion occurs, and choose a suitable extinguishing agent. Chemistry and IT practical: drag experimental data points so the computer builds a calibration curve A = ε·l·C, computes the correlation coefficient, and works out the concentration of an unknown sample.
Lesson: Chemical thermodynamics (enthalpy, entropy, Gibbs free energy); chemistry in fire and explosion prevention; chemistry and information technology practical
What it shows
Three extension topics share one simulation. Thermodynamics: ΔG = ΔH − TΔS shows that an endothermic reaction with a positive entropy change, such as the decomposition of limestone, becomes spontaneous only above a certain temperature, about 1110 K. Fire safety: the fire triangle and the explosive limits of methane, LPG and hydrogen explain when a gas–air mixture ignites or explodes, and how water, CO₂ and dry powder each remove one side of the triangle. Computing: linear regression fits a Beer–Lambert calibration line, A = ε·l·C, used to find an unknown concentration.
How to use
Move between topics with the Thermodynamics, Fire & Explosion and Chemistry & Computing tabs. In the first, drag the Reaction temperature and note where ΔG changes sign; press Change reaction to compare exothermic examples. In the second, set the Flammable gas concentration in air, press Ignite, then choose an Extinguishing agent. In the third, raise the Random error in absorbance measurement, press Re-measure data and watch the correlation coefficient.
Parameters you can change
- Current topic 1. Thermodynamics: ΔG = ΔH − TΔS, 2. Fire and explosion prevention, 3. Computer-aided chemistry practical
- Reaction temperature 300–1500 K
- Flammable gas in air Methane CH₄ (explosive at 5–15%), LPG (2.1–9.5%), Hydrogen H₂ (4–75%)
- Flammable gas concentration in air 0–30 %
- Extinguishing agent Not extinguished, Water (cools the fire), CO₂ gas (excludes oxygen), Dry powder (blocks the fuel)
- Random error in absorbance measurement 0–20 %
Questions to explore
- Above what temperature does the decomposition of CaCO₃ become spontaneous, and why does temperature decide this?
- Why does a methane–air mixture containing 20% methane not explode when a spark is applied?
- How does a larger measurement error affect the correlation coefficient and the calculated concentration of the unknown sample?
