Scientific accuracy policy

Atomic masses on Molar Mass Lab come from a consistent internal periodic table aligned with commonly taught standard atomic weights. Classroom answer keys may differ slightly when a course requires rounded textbook values (for example O = 16.00 exactly).

We report molar masses to three decimals in compound profiles so students can see intermediate arithmetic. Your teacher may ask for two decimals—round only at the end.

Safety and industrial process descriptions are educational summaries, not workplace SOPs. Always follow your institution's procedures. See the disclaimer.

Fact-checking preferences and citation expectations are described in our fact-checking policy.