burning and boiling both need heat but 1 is a physical change and 1 is a chemical change. what is the differen

Answer 1

Burning is a chemical change. Oxygen reacts with the material that you burn and converts it into the corresponding oxide. You start with one chemical and end up with another in the burning process. In the case of boiling, a liquid is converted into gaseous (vapour) state. Here the material is same; only its physical form is different before and after boiling. Hence it is a physical change.

Answer 2

Physical Changes:
Changes of state such as melting or boiling are physical changes and are generally easy to reverse though the end product may not always look exactly the same as the starting material. In physical changes no new materials are formed and the particles do not change apart from gaining or losing energy.

Melted wax solidifies when cooled but unless it is shaped or moulded it will not be the same shape as at the start. On a microscopic level although the same particles are present they may be in different places within the solid.
Ice is made up of particles of water. When it melts the water which is formed is made up the same water particles and when it boils the steam is also made up of the same water particles. Particles stay the same unless there is a chemical change whether the matter is solid, liquid or gas. Only their arrangement, energy and movement changes.

Chemical Changes:
For some materials chemical changes rather than physical changes are initiated by heat. In chemical changes new substances are formed and the process is often difficult to reverse. During chemical changes particles do change with atoms or ions regrouping . Bonds (links) between atoms break and new ones form and energy is either given out or taken in. Some chemical changes are initiated by mixing.

Children may be familiar with combustion reactions such as burning candles, wood or other fuel.
In chemical changes there are often signs of change such as

colour change
texture change (irreversible)
formation of solid, liquid or gas bubbles (effervescence)

Hope this helps x

Answer 3

Your incorrect I think? both burning & bioling ARE both chemical & physical changes. Both processes change the material at a fundmantal atomic level.

Burning transforms a substance utterly and completely for example take a piece of wood and burn it, its no longer wood is it. It becomes reduced and transformed into ash and carbon.

Another example take a substance like rice & boil it in water, a fundamental change in the grain does take place both chemically and physically. Before cooking the rice wasnt edible on its own now its trasformed by the bioling & heat into a different condition, one which allows humans to consume it. i.e. its been changed by heat and changed both chemically & physically.

Therefore its too simplistic to say 1 is a physical change and 1 is a chemical change, Both are true! IMO heat causes both physical and chemical change. How can you have one without the other? Its NOT black & white at all.

Answer 4

Boiling is endothermic, in that one has to put energy into the system to achieve the physical change in the state of the original materiel, cold water, to achieve boiling water and steam, however the resultant materiel is still water, H2O.

Burning is exothermic, in that once initially ignited, the materiels that are burning give off more heat than was originally put into the system. The end product is different as well. You start with a complex carbon based molecular materiel, for instance Methane CH4 or Ethane C2H6, together with oxygen O2, and, in a total combustion, end up with CO2 and H2O.

Answer 5

Boiling a liquid causes it to change from a liquid state to a gaseous state. That is a physical change. Boiling liquid water is water and steam is water - all H2O.

Burning is a chemical change. Wood or paper, for example will burn, combine with oxygen to form carbon and various gases.

Answer 6

Boiling water goes through a chemical change as it goes from a liquid to a gas but it can also return to it's original form. But if you burn something you have physically changed the properties and it cannot be changed back.

Answer 7

a simple way to think of it is: boiling the broth is a physical change because you can cool the liquid or gas back down and it goes back to its original form,
burning is a chemical change because you can never return the broth to its original form.

Answer 8

think of it this way can you turn a burned piece of paper back to it's original state you can with water if it can be returned it's not physcal if it cannot it is physcal and chemical can always be returned with out adding anything new to it

Answer 9

Burning is physical because it is touched whereas boiling is touched indirectly through water