# Tap OChem vs Diffusion and osmosis

The clearest difference is update cadence: Tap OChem at every 3 months against Diffusion and osmosis's every 30 months. Diffusion and osmosis's advantage is price ($0.99 vs $4.99). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Tap OChem costs $4.99 and Diffusion and osmosis $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Tap OChem ships an update every 3 months, Diffusion and osmosis every 30 months. The most recent releases landed on October 10, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Tap OChem | Diffusion and osmosis |
| --- | --- | --- |
| Price | $4.99 | **$0.99** |
| Rating | **[4.7 (39 ratings)](https://appshunter.io/ios/app/tap-ochem/id579861146/reviews)** | — |
| Number of ratings | **39** | — |
| Positive reviews | 91.7% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 30 months |
| Monetization | Paid | — |
| Size | 3.5 GB | 40 MB |
| Requires iOS | 13.2 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Tap OChem, LLC](https://appshunter.io/developer/579861209) | [www.ajaxmediatech.com](https://appshunter.io/developer/973768003) |

## What reviewers say

### Tap OChem

[App page](https://appshunter.io/ios/app/tap-ochem/id579861146)

Visualize complex organic chemistry reactions and concepts with animated explanations. This app covers a wide range of undergraduate organic chemistry topics, aiding in exam preparation and understanding of molecular behavior.

**Highlights:** Animated organic chemistry reactions, Detailed concept explanations, Electron pushing diagrams, Full-color text descriptions, MCAT, PCAT, OAT, DAT prep, Regular content updates

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Diffusion and osmosis

[App page](https://appshunter.io/ios/app/diffusion-and-osmosis/id1199769507)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Tap OChem free?

Tap OChem costs $4.99, with no in-app purchases.

### Is Diffusion and osmosis free?

Diffusion and osmosis costs $0.99, with no in-app purchases.

### Do Tap OChem or Diffusion and osmosis have ads?

Neither Tap OChem nor Diffusion and osmosis shows ads.

### Which is updated more often, Tap OChem or Diffusion and osmosis?

Tap OChem ships an update every 3 months, and Diffusion and osmosis every 30 months. Most recently, Tap OChem was updated on October 10, 2026 and Diffusion and osmosis on October 12, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*