No, not necessarily. An explosion might be be a sign of a chemical reaction (or a mechanical reaction, for that matter), since it's really just an enormous release of energy all at once.
Chemical reactions usually do exhibit some sort of observable change, though. For example, there may be a release or absorption of heat (in exothermic and endothermic reactions, respectively), a change in state of matter (solid, liquid, gas), or a change in color.
An explosion may be the result of a chemical reaction. Such is the case if we set off a stick of TNT. But it may be nuclear, as in the case of a nuclear weapon, or may be mechanical, as in the case of the blast created when a compressed gas cylinder with a failing weld is filled and blows up. There can be several causes for an explosion.
not always but frequently there is. some chemicals when you mix them together are harmless but some can cause dangerous side affects. most of the time there will be some chemical reaction or change of colour when you mix chemicals. :)
No, they may merely result in an increase in temperature. As an example acetic acid in vinegar reacts with magnesium hydroxide in milk of magnesia. The reaction does release energy, which can be noted as the temperature of the solution increases noticeably, but the only visible change is that the solution turns from white to clear.
Yes, chemical reactions always involve chemical changes. The definition of a chemical reaction is a chemical change that takes place when combining two or more chemical substances. Of course, not every substance present for a reaction will necessarily undergo a chemical change: some may exit the reaction as the same material, even if their presence serves to catalyze the reaction.
No, the vast majority do not.
Yes.
A reaction that emmits heat is called an exothermic reaction .
Some reactions give off heat (exothermic), others absorb heat (endothermic). All reactions increase entropy.
Endothermic reactions need heat. Exothermic reactions give off heat.
Lithium gradually reacts with water to give off hydrogen
No. The moon does not even give off light energy. It reflects light from the sun. This is a purely physical process.
A reaction that emmits heat is called an exothermic reaction .
but
It is sign of chemical reaction because smell and heat is produced.
As a result of a chemical reaction with gas release.
How could a chemist find out how much mass is given off as gas during a chemical reaction
substances can change to a solid, gas or liquid. solid - precipitate gas - fumes liquid - color change Either way, since its a chemical reaction, there always will be a change in the chemical composistion of a substance.
Effervescent, I believe.
fire is a chemical reaction
Smell
A chemical change or reaction happens if new substances are formed. there may be a change in temperature so the reaction mixture may heat up or cool down. it also might change colour, give off bubbles of gas or fumes and you also might hear fizzing or a gas might explode.
The amount of mass given off as gas during a chemical reaction depends on the stoichiometry of the reaction and the molar mass of the gas produced. It can be calculated using the ideal gas law, which relates the pressure, volume, temperature, and number of moles of a gas.
Some reactions give off heat (exothermic), others absorb heat (endothermic). All reactions increase entropy.