How to Write an Active Vs Passive Voice for Chemistry

Chemistry writing requires a delicate balance between objective reporting and clear narrative flow. While traditional lab reports often rely on the passive voice to emphasize the chemicals and reactions over the researcher, modern journals like the Journal of the American Chemical Society (JACS) increasingly value the active voice for discussing interpretations and theoretical implications.

What Is an Active Vs Passive Voice in Chemistry?

In chemistry, the active voice places the agent (the researcher or the chemical species) as the subject performing the action, such as 'The catalyst accelerated the reaction.' The passive voice shifts the focus to the recipient of the action, such as 'The reaction was accelerated by the catalyst.' Chemistry writing is unique because it uses passive voice to maintain objectivity in the Experimental Section but often switches to active voice in the Discussion to show the author’s intellectual contribution.

Before You Start

• Review the 'Instructions for Authors' for your target journal, such as Nature Chemistry or RSC Advances, as their voice preferences differ.
• Identify the primary focus of your sentence: is it the procedure (passive) or the interpretation (active)?
• List your key reagents, catalysts, and analytical instruments to ensure they are the subjects of your active sentences when describing mechanisms.
• Determine if your instructor requires the formal 'third-person passive' for lab notebooks.

Use Passive Voice for Experimental Procedures

When describing the synthesis of a compound, the focus should be on the chemicals and the conditions, not the person performing the titration. Use the passive voice to achieve an objective, reproducible tone.

Example: Passive: 'The solution was stirred for 12 hours at room temperature.'

Tip: Avoid starting sentences with 'I' or 'We' during the experimental methodology section to keep the focus on the chemical process.

Employ Active Voice for Chemical Mechanisms

When explaining how a nucleophile attacks an electrophile, the active voice is more direct and easier to follow. It allows the molecules to act as the 'characters' in your scientific narrative.

Example: Active: 'The lone pair on the nitrogen atom attacks the carbonyl carbon.'

Tip: Treat chemical species as the subjects of your sentences to make your mechanism descriptions more dynamic.

Switch to Active Voice for Data Interpretation

In your Discussion section, use the active voice to state what your data suggests or proves. This clarifies your intellectual claim and makes your argument more persuasive.

Example: Active: 'The FTIR spectra confirm the presence of a hydroxyl group at 3400 cm⁻¹.'

Tip: Use active verbs like 'demonstrate,' 'suggest,' 'indicate,' and 'confirm' when discussing your results.

Use Passive Voice to Emphasize the Sample

If the most important part of the sentence is the sample or the instrument used, the passive voice is appropriate. This is common in the Results section when describing characterization.

Example: Passive: 'The crystalline structure was characterized using X-ray diffraction (XRD).'

Tip: Check if the 'actor' (the researcher) is irrelevant to the outcome; if so, the passive voice is usually better.

Identify and Replace Dangling Participles

Chemistry students often create 'dangling modifiers' when trying to avoid the first person. Ensure the subject of your sentence is the one actually performing the action described in the opening phrase.

Example: Incorrect: 'After heating the flask, the precipitate was filtered.' (The precipitate didn't heat the flask). Correct: 'After the flask was heated, the precipitate was filtered.'

Tip: Read your sentences aloud to ensure the logic of the action matches the subject of the sentence.

Use Active Voice to Describe Figure Content

When referring to figures or tables in your report, the active voice is more concise and directs the reader's attention effectively.

Example: Active: 'Figure 1 shows the relationship between temperature and reaction rate.'

Tip: Instead of saying 'It is shown in Figure 1 that...', simply say 'Figure 1 illustrates...'

Balance Voice in the Abstract

A chemistry abstract should use a mix: passive voice for the work performed and active voice for the significance of the findings.

Example: Mixed: 'A new gold-catalyzed synthesis was developed (passive). This method provides a greener alternative to traditional cross-coupling (active).'

Tip: End your abstract with a strong active-voice sentence regarding the impact of your research.

Common Mistakes to Avoid

• Using 'We' excessively in the Experimental section, which can come across as informal in chemistry reporting.
• Overusing the passive voice in the Discussion, leading to wordy and 'muddy' explanations of chemical trends.
• Creating 'passive-aggressive' sentences where the agent is hidden, making it unclear who performed a specific calculation or measurement.
• Mixing voices inconsistently within the same paragraph of a lab report.
• Using the passive voice for simple observations, e.g., 'A color change was seen,' instead of 'The solution turned blue.'

Pro Tips

• Check the 'ACS Style Guide' for the most authoritative stance on voice in chemical literature.
• Use active voice when comparing your results to literature values to clearly distinguish your findings.
• If you find yourself using 'It was found that' repeatedly, delete the phrase and start the sentence with the data point.
• Reserve 'I' for personal reflections in lab notebooks, but use 'We' in collaborative papers for interpretative statements.
• Use the active voice to describe the limitations of a specific spectroscopic method.

Frequently Asked Questions

Is it okay to use 'I' or 'We' in a chemistry paper?

Yes, modern chemistry journals like those from the Royal Society of Chemistry (RSC) allow 'We' in the Introduction and Discussion to describe the authors' choices or interpretations. However, avoid 'I' in formal reports unless specifically instructed.

Why is the passive voice preferred in the Experimental section?

The passive voice emphasizes the process and the materials rather than the researcher. In chemistry, the experiment should be reproducible by anyone, so the specific 'actor' is considered irrelevant to the methodology.

Does active voice make chemistry writing less professional?

Not at all. In fact, the active voice often makes complex chemical arguments easier to read by reducing word count and clarifying the relationship between variables.

Should I use active or passive voice for my thesis conclusion?

The conclusion should primarily use the active voice to state the implications of your work and your final deductions, as this highlights your contribution to the field.

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