exothermic reaction
When energy is released in a chemical reaction it is called an exergonic reaction. One example of an exergonic reaction is cellular respiration in both plants and animals. It is represented by a negative change in free energy (-∆G).
An exothermic reaction is only the release of energy as heat, so the more correct answer would be an exergonic reaction, which is the release of energy.
I think that you are inquiring about "exothermic" and "endothermic" chemical reactions. In an exothermic reaction heat is released to the surroundings during the reaction. In an endothermic reaction heat is absorbed from the surroundings as the reaction takes place. That is, in the endothermic case heat energy has to be supplied from the surroundings.
Carrying out a search with one, or both, of these words as search terms, plus "chemical reaction" will, I am sure, give you actual examples of each type of reaction.
In some reactions like the combusion of coal or wood energy is released.
In these reactions the energy required to form the product is less than the energy released.
Such Reactions are called "EXOTHERMIC REACTIONS".
That depends on the type of energy being absorbed or released or exchanged.
a chemical change is taking place
It is a physical change.
No. Fireworks are an example of a chemical change called combustion.
Because chemical bonds are not formed or broken by a phase change.
That depends on the type of energy being absorbed or released or exchanged.
Yes it is released/ absorbed during chemical changes.
When one or more new substances is created, the change is called a chemical change. A chemical change has occurred if there is a new substance created, there was energy released or absorbed, or the substances no longer exhibit the same chemical properties.
It depends. There are two types of chemical reaction int his sense. Exothermic reactions release energy and endothermic reactions absorb it.
Energy can be absorbed or released in a chemical or physical change, it is not destroyed or created. It simply assumes a different form.
a chemical change is taking place
It depends on whether or not the chemical reaction is exothermic or endothermic. If exothermic, then yes, energy is released. If endothermic, then no, energy is absorbed, not released.
It is a physical change.
Chemical bonds are made and broken by chemical reactions. After chemical bonds have been broken, then energy is released, and if a chemical bond is made, then energy is absorbed.
melting point
No, a change in matter can't take place without energy being released or absorbed? Why? Well, this is because every chemical or physical change in matter includes a change in energy. You can't change matter without a change in energy. Energy is the ability to do work or cause change. Hope you find this helpful. And yes, this answer has been approved by my science teacher.
Heat absorption is a physical change. It can cause a change in state and/or a temperature increase, but the matter that is absorbing the heat does not change. It retains all of its physical and chemical properties that it had before absorbing the heat.