Concentration after evaporation calculator
See how strong a solution gets when solvent boils or dries off: evaporating 40 mL from 100 mL of a 2 M solution leaves 60 mL at 3.33 M, a factor of 1.67. The solute is assumed to stay behind. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Initial concentration
- 2
- Initial solution volume
- 100
- Evaporated volume
- 40
- C1
- 2
- V1
- 100
- V evap
- 40
- Final volume
- 60
A concentration after evaporation calculator answers a routine lab and homework question: if solvent leaves a solution and solute stays behind, what is the new concentration? Prep of stock reagents by gentle evaporation, sauce reduction analogies in process chemistry, environmental water samples after open-air drying, and coding kata expected values all need that same deterministic C2 without a spreadsheet.
What concentration after evaporation means physically
When only solvent leaves a homogeneous solution and the dissolved solute does not leave with the vapor, the absolute amount of solute is conserved. That amount can be written as the product of concentration and volume in consistent units: initial amount equals C1 times V1, and after evaporation the same amount equals C2 times V2, where V2 is the remaining liquid volume. Solving for the unknown final concentration gives C2 equals C1 times V1 divided by V2.
The evaporated volume is the difference V1 minus V2, so equivalently C2 equals C1 times V1 divided by the quantity V1 minus V_evap. Concentrations C1 and C2 must share the same unit—both molar, both mass per volume, both percent, both parts per million—because the equation cancels concentration units only when they match. Volumes V1, V_evap, and V2 likewise must share one volume unit.
The model assumes ideal conservation with no solute loss, no precipitation, and no volume change from temperature beyond what you already encoded in the volumes you enter. If evaporated volume is greater than initial volume the remaining volume would be negative, which is impossible; if they are equal the remaining volume is zero and concentration is undefined.
The concentration factor V1 over V2 equals C2 over C1 whenever C1 is positive, which is a quick sanity check: losing forty percent of the volume multiplies concentration by about one point six seven.
Practical tips, limits, and related searches
Keep volumes in the same unit and concentrations in the same unit before you call; this capability does not convert milliliters to liters or molarity to mass percent. Prefer numbers over pre-formatted strings when you control the client; string numbers are accepted only when they match a strict finite numeric pattern. Near-total evaporation with a tiny remaining volume produces a very large C2 and may hit the absolute result cap of one trillion—reduce magnitudes or stop earlier in the process if you need an intermediate concentration.
This landing targets people searching for concentration after evaporation, solvent evaporated calculator, or how concentration changes when volume decreases; it is not a full multi-component distillation simulator, not a C1V1 equals C2V2 dilution solver for adding solvent, and not a boiling-point elevation tool. Prefer the dilution calculator when you are adding solvent to lower concentration; prefer this capability when solvent is leaving and concentration must rise.
What you can do with it
Lab prep by gentle solvent evaporation
Analysts concentrate a stock by evaporating known solvent volume and need the new molarity or mass-per-volume before the next dilution step.
Homework checks for conservation problems
Students enter C1, V1, and evaporated volume from textbook word problems and compare hand-written C2 and remaining volume against a deterministic result.
FAQ
How is final concentration calculated after evaporation?
Solute is conserved: C1·V1 = C2·V2 with V2 = V1 − V_evap, so C2 = C1·V1 / (V1 − V_evap). Concentration units stay the same as C1.
Is this the same as the C1V1 = C2V2 dilution calculator?
Related identity, opposite process. Dilution adds solvent and lowers concentration; this tool models solvent loss and rising concentration from known evaporated volume.
Do concentration and volume units need to match?
C1 and C2 share one concentration unit; V1, evaporated volume, and V2 share one volume unit. The calculator does not convert units for you.
Is the concentration after evaporation calculator free?
The browser tool is free and runs locally.
What happens if all of the solvent evaporates?
The calculator rejects it. If the evaporated volume equals or exceeds the starting volume, no liquid is left and the concentration has no meaning, so the volume lost must stay below the starting volume.
Related tools
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
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/concentration-after-evaporation \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"initial_concentration":2,"initial_volume":100,"evaporated_volume":40}'const res = await fetch("https://api.kit.forhosting.com/chem/concentration-after-evaporation", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"initial_concentration": 2,
"initial_volume": 100,
"evaporated_volume": 40
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/chem/concentration-after-evaporation",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"initial_concentration": 2,
"initial_volume": 100,
"evaporated_volume": 40
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/chem/concentration-after-evaporation", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"initial_concentration":2,"initial_volume":100,"evaporated_volume":40}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"initial_concentration":2,"initial_volume":100,"evaporated_volume":40}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/chem/concentration-after-evaporation", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"initial_concentration": 2,
"initial_volume": 100,
"evaporated_volume": 40
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "chem.concentration_after_evaporation",
"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
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_abs | 1000000000000 |
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. |
Technical notes
When the evaporated volume meets or exceeds the initial volume the remaining volume is zero or negative, so the API returns a clear invalid_input error instead of Infinity or a silent clamp.
What concentration after evaporation means physically
Both cases are rejected as invalid_input so callers never receive non-finite results.
How to call the API and what comes back
Initial concentration must be non-negative; initial volume must be strictly positive; evaporated volume must be non-negative and strictly less than initial volume so the remaining volume stays positive. Send a JSON body with three required finite numbers: initial_concentration (aliases c1, C1, concentration, conc, c_initial), initial_volume (aliases v1, V1, volume, vol_initial, v_initial), and evaporated_volume (aliases v_evap, evaporated, volume_evaporated, lost_volume, solvent_lost). Absolute values must stay within the published limit of one trillion so intermediate products remain finite in IEEE double precision on the Worker and in the browser. On success the response echoes rounded initial_concentration and c1, initial_volume and v1, evaporated_volume and v_evap, sets final_volume and v2 to V1 minus V_evap, final_concentration and c2 to the computed C2, concentration_factor to V1 over V2, solute_amount and product_c1v1 to C1 times V1, product_c2v2 to C2 times V2 for a conservation check, formula to the string C2 equals C1 times V1 over V1 minus V_evap, equation to a filled C1 V1 equals C2 V2 line, message to a short English summary, and steps to an ordered array of substitution lines. Failed validation—missing fields, non-finite numbers, values outside absolute limits, negative concentration or evaporated volume, non-positive initial volume, or evaporated volume that equals or exceeds initial volume—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.
Practical tips, limits, and related searches
When teaching, pair examples: C1 equals two with V1 equals one hundred and forty milliliters evaporated leaves sixty milliliters and C2 equals about three point three three; zero evaporated volume leaves concentration unchanged; evaporated volume larger than V1 demonstrates the hard invalid_input path. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately set evaporated volume above the initial volume. Round-trip checks are easy: recompute V2 by hand, verify C1 times V1 equals C2 times V2 within the same twelve-decimal rounding, and confirm that concentration_factor times C1 recovers C2 when C1 is positive.
Integration use cases
Unit tests for process chemistry helpers
Generate known-good concentration-increase cases plus deliberate over-evaporation rejections for coding kata and CI expected values.
Technical questions
What if evaporated volume exceeds initial volume?
The remaining volume would be negative or zero, so the tool returns invalid_input instead of Infinity or a clamped value.