Calculadora de Ponto de Ebulição
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
ΔTb = Kb · m · i ; Tb = Tb₀ + ΔTb
About this calculator
The Boiling Point Calculator determines the boiling temperature of a solution based on boiling point elevation, using the formula ΔTb = Kb × m × i. The solution's boiling point (Tb) is the sum of the pure solvent's boiling point (Tb₀) and the increase ΔTb. The calculator takes into account the solvent's ebullioscopic constant (Kb), solution molality (m), and van 't Hoff factor (i), which indicates the number of particles formed upon dissolution.
Operation is straightforward: the user inputs the pure solvent's boiling point, ebullioscopic constant, molality, and factor i. The tool automatically calculates the elevation ΔTb and the new boiling point. For example, for a 1 molal aqueous NaCl solution (i=2), with water's Kb = 0.512 °C·kg/mol, ΔTb is 1.024 °C, raising the boiling point from 100 °C to 101.024 °C.
This calculator is useful for chemists, engineers, and students needing to predict colligative properties of solutions. It is applied in laboratories, food industries (concentration control), pharmaceuticals, and teaching chemical thermodynamics. It also aids in designing distillation and evaporation processes.
Caveats: the model assumes ideal and dilute solutions; for concentrated solutions or complex ionic interactions, results may be approximate. Ensure the solvent is appropriate (Kb is solvent-specific). Factor i should reflect actual dissociation: for weak electrolytes, use the degree of dissociation. Remember that ambient pressure affects boiling point; the calculator assumes standard pressure (1 atm).
Frequently asked questions
What is the ebullioscopic constant (Kb) and how do I find its value?
The ebullioscopic constant is a solvent property indicating the boiling point elevation for a 1 molal solution. Its value is tabulated for each solvent (e.g., water = 0.512 °C·kg/mol, ethanol = 1.22 °C·kg/mol). Consult tables of ebullioscopic constants.
How do I determine the van 't Hoff factor (i) for a solute?
For strong electrolytes, i equals the number of ions formed (e.g., NaCl → i=2, CaCl₂ → i=3). For non-electrolytes, i=1. For weak electrolytes, use i = 1 + α(n-1), where α is the degree of dissociation and n is the number of ions.
Does this calculator work for any solvent?
Yes, as long as you provide the pure solvent's boiling point and its ebullioscopic constant. The formula is general, but accuracy depends on solution ideality.
What if the solution is very concentrated?
For concentrated solutions, the formula may be inaccurate because it assumes ideal behavior. In such cases, consider using activity coefficients or more advanced models.
Does atmospheric pressure affect the result?
Yes, boiling point varies with pressure. The calculator assumes standard pressure (1 atm). If pressure differs, adjust the solvent's Tb₀ according to local pressure.