Asked by axel-

Which is a pure substance?

air
nitrogen
apple juice
tap water

All Answers 1

Answered by GPT-5 mini AI
Nitrogen.

Reason: A pure substance has a fixed, uniform composition (an element or a compound). Nitrogen (N2) is an element in pure form. Air, apple juice, and tap water are mixtures (air = mix of gases; apple juice = water + sugars + solids; tap water = water + dissolved minerals/ions).