Normally there is some energy change. Heat and/or light may be given off.
By a change in color, a precipitate, or a gas.
There will be a gain in mass.....but you can't predict the new change in mass unless you weigh the products after the chemical change occurred.
Some characteristics of a chemical change are: - change of smell - change of color - release of gases - change of temperature - formation of a precipitate - change of the aspect - change of pH in solutions - change of viscosity - flames or explosion etc.
The production of smoke from something burning would be a sign of a chemical change. Broken pieces, change in shape, or change in state are all physical changes.
When chemical change has occurred, it means that the object has become something that it will be forever until changed again. For example, when you burn paper, it has become something new, a new substance. That paper has become ashes and will never be paper again.
You would recognize a precipitate formation when a solution turns cloudy or when solid particles start appearing and settling at the bottom of the container. This indicates that a chemical reaction has occurred, resulting in the formation of a solid product known as a precipitate.
You can determine if a chemical change has occurred by looking for signs such as a change in color, formation of a precipitate, evolution of gas, or release of heat or light. Additionally, if the chemical composition of the substance has been altered, it is likely that a chemical change has taken place.
i want to know the answer.............................................................................................................................................................................. .................................................................................................................................. ................................................................................................................................................ .................................................................................................................................................... ................................................................................................................................. ...................................................................................................................................... but I don't!
You can tell a chemical reaction has occurred if there is a change in color, formation of a gas or solid precipitate, evolution of heat or light, or a change in odor. Additionally, changes in the chemical composition, such as the breaking or forming of bonds between atoms, indicate a chemical reaction has taken place.
Physical, because each slice of pellet is still the same chemically: you have merely divided your one sodium block into two blocks of sodium. If it were chemical, some kind of notable chemical difference would have occurred (you would no longer have sodium, but something else).
For a chemical change to occur, there must be a chemical reaction. A chemical reaction would be either endothermic (uses energy, mostly heat), or exothermic (produces energy, again mostly heat). Any change in temperature of the reactants, as measured by a thermometer, will tell you not only ifa chemical reaction occurred, but also which kind of chemical reaction. No temperature change usually indicates that no reaction has occurred, a decrease in temperature would indicate an endothermic reaction, while an increase in temperature would indicate an exothermic reaction.
Some indicators of a chemical reaction are:- change of color- change of odor- release of a gas- change of the temperature- change of the viscosity- formation of a precipitate- change of general appearance- possible explosion- possible chemiluminescence -formation of new compounds