What is the mass of fire

Fire is a chemical reaction, rapid oxidation, and cannot have mass.

Flame is a mixture of hot gases, and if a fire is hot enough to ionize the gaseous components, it can become a plasma.

Therefore, flame has mass, but fire doesn't.

It depends on what you consider "fire" to be.

If you consider fire to be the energy that's given off during combustion, then it's zero, because energy does not have mass.

If you consider fire to be the matter undergoing combustion, then it depends on what flammable gases are reacting to the Oxygen in the air.

If you consider fire to be an object itself, then it sounds to me like you need to do some research.

Fire is not matter so it does not have mass.

The term "fire" refers to the rapid oxidation of a material during the process of combustion. This reaction releases heat, light, and the various reaction products. The reaction products themselves may have negligible mass, but the heat and light do not.

Some good theoretic answers, but if you lit a candle (or a fireplace, but it's impractical) and somehow put a jar over it to "catch" the flame, it would have mass because of the byproducts and gases. It would snuff the flame, but what you got in the jar would have mass. But pure energy has no mass, true.

A theoretical, imaginary answer to a theoretical, imaginary question is....
The mass of fire is ALL combustion products collected, and added together and weighed.
This mass must be equal to the mass of reactants