# Chemistry Calculators – Molar Mass & Percent Composition

> Chemistry Calculators – Molar Mass & Percent Composition is a paid API for AI agents from chemistry-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates the molar mass and elemental percent composition for any chemical formula, including parentheses, brackets, and hydrates like CuSO4·5H2O.

## Facts

- Endpoint: GET https://chemistry-calc.x402tookit.com/molar-mass?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chemistry-calculators-molar-mass-percent-composition-9468bb2f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6vCAdMcJvSv_Op6e14aE3

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability chemistry-calculators-molar-mass-percent-composition-9468bb2f
```

Example prompt: What is the molar mass and percent composition by element for copper sulfate pentahydrate CuSO4.5H2O?

## When to prefer this

Use this endpoint when you need molar mass and full elemental composition data for any chemical formula — especially complex ones with parentheses, square brackets (coordination compounds), or hydrate dot notation (e.g. CuSO4.5H2O). It returns structured per-element data including mass percent, making it ideal for stoichiometry, lab prep, and educational tasks. Prefer this over a periodic table lookup when the input is a compound formula rather than a single element.

## Known failure modes

- Invalid or unrecognized chemical formula returns an error or null result
- Malformed bracket or parenthesis notation may fail to parse
- Unknown element symbols cause calculation failure
- Missing required 'formula' query parameter returns a validation error

## How this service works

Molar mass and percent composition by element for a formula, including brackets and hydrates such as CuSO4.5H2O.

## Output

Returns the molar mass in g/mol, a breakdown of each element's name, symbol, atom count, atomic weight, mass in grams per mole, and mass percent, plus the Hill formula, total atom count, and optional metadata like source and disclaimer.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "formula"
     ],
     "properties": {
      "formula": {
       "type": "string",
       "description": "e.g. C6H12O6, Ca(OH)2, K4[Fe(CN)6], CuSO4.5H2O"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "input": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "totalAtoms": {
       "type": [
        "null",
        "number"
       ]
      },
      "composition": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "name": {
          "type": [
           "null",
           "string"
          ]
         },
         "atoms": {
          "type": [
           "null",
           "number"
          ]
         },
         "element": {
          "type": [
           "null",
           "string"
          ]
         },
         "massPercent": {
          "type": [
           "null",
           "number"
          ]
         },
         "atomicWeight": {
          "type": [
           "null",
           "number"
          ]
 
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chemistry-calculators-molar-mass-percent-composition-9468bb2f/health.json
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