---
title: "The Contact process Template – Chemistry Diagram | MolDraw"
url: https://www.moldraw.com/templates/school-contact-process/
description: "The Contact process template: Sulfuric acid manufacture for GCSE, A-level and NCERT: sulfur burner, V₂O₅ converter at about 450 °C and 1–2 atm (2SO₂ + O₂ ⇌…"
lang: en
publisher: Scidart Academy
generated: 2026-11-13
---
[MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [General & inorganic](https://www.moldraw.com/templates/general-and-inorganic/) › The Contact process

[General & inorganic](https://www.moldraw.com/templates/general-and-inorganic/)Premium

# The Contact process template

![The Contact process template: Sulfuric acid manufacture for GCSE, A-level and NCERT: sulfur burner, V₂O₅ converter at about 450 °C and 1–2 atm (2SO₂ + O₂ ⇌ 2SO₃, ΔH = −197 kJ mol⁻¹), absorption of SO₃ in concentrated H₂SO₄ to oleum and dilution, with the V₂O₅ redox cycle and the choice of conditions.](https://www.moldraw.com/templates/school-contact-process.webp)

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Sulfuric acid manufacture for GCSE, A-level and NCERT: sulfur burner, V₂O₅ converter at about 450 °C and 1–2 atm (2SO₂ + O₂ ⇌ 2SO₃, ΔH = −197 kJ mol⁻¹), absorption of SO₃ in concentrated H₂SO₄ to oleum and dilution, with the V₂O₅ redox cycle and the choice of conditions.

## What the template shows

- Sulfur → SO₂ → SO₃ over V₂O₅ at about 450 °C and 1–2 atm → oleum → sulfuric acid
- Plant flow
- Sulfur burner
- molten S + dry air
- Gas cleaning
- dust removed, gas dried
- (would poison V₂O₅)
- cooled between beds
- Absorption tower
- oleum + water
- excess air (O₂)
- The four stages
- Choosing the conditions
- sulfur burned in dry air · ΔH = −297 kJ mol⁻¹
- V₂O₅ catalyst, ≈ 450 °C, 1–2 atm · ΔH = −197 kJ mol⁻¹
- absorbed in 98% sulfuric acid: oleum (fuming sulfuric acid)
- oleum diluted with water
- How V₂O₅ works (A-level)
- V +4 → +5: catalyst regenerated
- Exothermic: low T gives more SO₃, but slowly
- 1–2 atm: yield already > 99%
- Faster; yield unchanged
- V₂O₅ (vanadium(V) oxide)
- Excess O₂ shifts the position right

Drawn with 37 shapes – every one editable in MolDraw.

## Sources

- [Housecroft & Sharpe, Inorganic Chemistry, 5th ed., Pearson 2018, ch. 16](https://openlibrary.org/isbn/9781292134147) Textbook
- [NCERT, Chemistry Part I, Class XII (pre-2023 edition), ch. 7 The p-Block Elements](https://ncert.nic.in/) Textbook

## How to use this template

1. Press **Edit in MolDraw**. The template opens on the canvas of the free MolDraw editor.
2. Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need.
3. Add your own structures, arrows and text next to it, or combine several templates on one page.
4. Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers.

## Frequently asked questions

### Is the The Contact process template free?

You can preview the The Contact process template here and open and edit it in MolDraw for free. Downloading or exporting it is part of MolDraw Pro, together with the other premium templates.

### Can I edit the The Contact process template?

Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it.

### Is the chemistry checked?

Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page.

### Which MO diagrams are included?

H₂ and He₂, N₂ and O₂ (showing s–p mixing and paramagnetic O₂), and carbon monoxide.

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