Answer:
Fire is hot because thermal energy (heat) is released when chemical bonds are broken and formed during a combustion reaction. Combustion turns fuel and oxygen into carbon dioxide and water. Energy is required to start the reaction, breaking bonds in the fuel and between oxygen atoms, but much more energy is released when atoms bonds together into carbon dioxide and water.
Fuel + Oxygen + Energy → Carbon Dioxide + Water + More Energy
Both light and heat are released as energy. Flames are visible evidence of this energy. Flames consist mostly of hot gases. Embers glow because the matter is hot enough to emit incandescent light (much like a stove burner), while flames emit light from ionized gases (like a fluorescent bulb). Firelight is a visible indication of the combustion reaction, but thermal energy (heat) may be invisible, too.
Explanation: