How Is Burning Wood A Chemical Change?(Know The Answer)

Burning wood is often confused with chemical or physical changes. According to the theory of chemical change, it is clearly a chemical change.  So, how is burning wood a chemical change?

Burning wood changes the product into another. Wood turns into ash and smoke, and there is no way to reverse them into wood again. As the change is irreversible and forms totally different substances, it’s a chemical change.

It’s impossible to realize why wood burning is not considered physical change if you don’t have a solid idea about the theories of these changes. Let’s check how is wood burning a chemical change and why not a physical change.

2 Main Reasons Why Wood Burning Is A Chemical Change: Proved

When one material changes into another with new properties, it’s a chemical change. There’s no doubt that wood burning is a chemical change. Let’s find out more in detail. 

1. Irreversible

This is one primary reason why wood burning is a chemical change. During wood burning, the wood turns into ash. So, it can’t be reversed. It’s not possible to reverse the ash into the wood at any cost. When the change is irreversible, it’s a chemical change.

2. Formation Of New Substances

When a change or reaction forms new substances, it’s a chemical reaction or chemical change. Wood burning forms new substances. During a chemical change, a substance’s molecular composition is entirely changed. 

The substances of wood are completely different from those that are formed after burning. Wood burning changes the wood into carbon dioxide gas, water vapor, and ash. So, there are no similarities between the substances. Hence, it’s a chemical change.

Why Burning Wood Is Not A Physical Change: Read Now 

There is confusion about why burning wood is not a physical change. Physical change is the change of matter, colour, odour, etc. A physical change doesn’t change the composition or the chemical nature of the material. In a physical change, only the material’s physical properties change.

It would be a physical change if the ash could be turned into wood again. As the wood burning turns the wood into ashes, it’s not a physical change any more.  

On the other hand, Cutting wood is a physical change. This turns the wood into pieces with no new substances. If you are cutting wood and making a chair with the wood chair, it’s still a physical change.

Chemical Reaction During Wood Burning: Check What Happens

Wood is mostly cellulose of interlinked glucose molecules(C6H12O6). There are some key nutritional elements present in the wood(Ca). So, the final chemical formula of wood is C6H12O6 + Ca. To keep the fire burning, you need enough fuel and Oxygen. Here, O2 is considered the chemical formula for fire. 

Let’s check what happens during wood burning. 

2 C6H12O6 + 2 Ca + 13 O= 2 CaCO3 (ash) + 10 CO2 +   H2O + Energy

Here, 2 C6H12O6  + 2 Ca is wood.

The wood turns into ashes and water vapor.  Also, the energy that holds carbons and hydrogen together gets dissipated. This is what happens when you are burning wood. As you can see now, there are no similarities between the chemical formulas before and after the burning, so it’s clearly a chemical change.


What Is A Chemical Change?

A chemical change occurs when two substances combine to create a new substance that is completely different from the previous one. It’s quite easy to detect if a change is physical or chemical. 

If the change forms a new product, it’s a chemical change, and the product will be irreversible. This means you won’t be able to bring it back to its previous stage. Burning wood, paper, or cake baking are examples of chemical change. 

What Is The Chemical Reaction Of Burning Wood?

The chemical change of wood substances starts the moment it catches fire. Wood is basically formed with glucose and some key nutritional elements. They change into ash, water vapor, and energy after the burning.

Doesn’t matter what the fuel is or what kind of wood you are burning, the chemical reaction always remains the same.

Can You Burn Old Pressure-Treated Wood?

Well, it’s not recommended to burn pressure-treated wood as they are highly hazardous. The fly ash from one minute of burning wood may contain serious health consequences. Burning pressure-treated wood is illegal and isn’t good for health and even for the environment as well.

There will be toxic ash and smoke if you are burning pressure-treated wood. Burning wood does not destroy arsenic or other chemicals. The pressure-treated wood sometimes comes with warning stamps to save people from hazards. 

Can You Burn Petrified Wood?

It’s not possible to burn purified wood as fire won’t catch petrified wood.

Petrified wood is not like regular wood. When wood turns into stone or rock by being buried in water or volcanic ash, they are formed into petrified wood. Normal wood pieces take a long time to form into petrified wood.

It’s tough to make any chemical change to petrified wood. This is why petrified wood is used for jewelry and for crafting decorative pieces.

Final Thoughts

I guess you are no more confused about how is burning wood a chemical change. By cutting the wood, it will undergo a physical change, and by burning it, it will undergo a chemical change. Once the wood is burned, it will turn into completely different substances. 

The chemical reaction proves that it’s a chemical change. When you burn wood, the formula of the products changes completely. 


Don’t burn pressure treated wood. (2018, October 4). North Carolina Coastal Federation. Retrieved February 4, 2023, from

Mulrow, J. (2020, December 7). Thinking Circular, with Chemistry. Plant Chicago. Retrieved February 4, 2023, from

Petrified wood. (n.d.). Wikipedia. Retrieved February 4, 2023, from

About Sam Maxi

Hi, this is Sam Maxi. I love talking about woodwork tools and my reviews are mostly based on the experience I have from my work. Apart from reviewing, I am a huge fan of surfing. Also, I love watching horror genre movies.

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