ForHosting KIT · Developer Utilities

Molar mass from boiling point elevation

This molar mass from boiling point elevation calculator returns the solute molar mass M in grams per mole from the measured boiling-point rise ΔTb, the solvent ebullioscopic constant Kb, the mass of solute in grams, and the mass of solvent in kilograms using the closed form M equals Kb times grams divided by ΔTb times kilograms.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Colligative boiling-point elevation links temperature rise to molality; rearranging ΔTb equals Kb times m with m equals moles of solute per kilogram of solvent yields the unknown molar mass without needing a molecular formula. The same identity appears in general chemistry labs that measure the boiling temperature of a solution, in identification of unknowns from colligative data, and in homework that gives elevation instead of moles. Typical textbook checks include water-like Kb about 0.512 K·kg/mol with ΔTb equals 0.256 K, five grams of solute, and 0.1 kg of solvent yielding M equals 100 g/mol, and a doubled elevation of 0.512 K with the same masses yielding M equals 50 g/mol. The engine uses only finite arithmetic with no network calls, no sampling, and no date-dependent shortcuts. Use it free in the browser for homework and lab prep, or call the API at $0.002 per successful request when you need identical molar-mass fixtures in CI, tutoring software, or teaching demos.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/chem/molar-mass-from-bp-elevation

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/chem/molar-mass-from-bp-elevation \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"elevation":0.256,"kb":0.512,"solute_grams":5,"solvent_kg":0.1}'

const res = await fetch("https://api.kit.forhosting.com/chem/molar-mass-from-bp-elevation", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "elevation": 0.256,
    "kb": 0.512,
    "solute_grams": 5,
    "solvent_kg": 0.1
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/chem/molar-mass-from-bp-elevation",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "elevation": 0.256,
    "kb": 0.512,
    "solute_grams": 5,
    "solvent_kg": 0.1
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/chem/molar-mass-from-bp-elevation", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"elevation":0.256,"kb":0.512,"solute_grams":5,"solvent_kg":0.1}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"elevation":0.256,"kb":0.512,"solute_grams":5,"solvent_kg":0.1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/chem/molar-mass-from-bp-elevation", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "elevation": 0.256,
  "kb": 0.512,
  "solute_grams": 5,
  "solvent_kg": 0.1
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "chem.molar_mass_from_bp_elevation",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Limits

max_abs_value 1000000000000000

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →

Run — free