0
Some indicators of a chemical reaction are:
- formation of new compounds - change of color
- change of odor
- release of a gas
- change of the temperature (absorption or release)
- change of the viscosity
- formation of a precipitate
- change of general appearance
- possible explosion - sometimes a sound is produced - possible chemiluminescence
Wiki User
∙ 6y ago
Add your answer:
Earn +20 pts
What happens to the composition of a substance during a chemical change?
Atoms are rearranged, heat may be given off, changes in color and odor might occur, or a gas or precipice may be formed. The composition is changed, and the above are signs of a chemical change.
What are some chemical reactions?
some chemical reactions take place when a chemical is added to a metal. sometimes the chemicl turns cloudy, it may fizz or a coat of black may appear on the piece of metal. hope this helps! :)
How do you know if a chemical reactions has taken place?
Signs of chemical reactions may be: - Gas release - Formation of a precipitate - Change of color - Change of odor - Change of pH - Change of aspect - Change of viscosity - Change of the temperature - Visible formation of new compounds
Atoms may combine in chemical reactions to form?
Reactants (apex)
What laboratory evidence do you need to show that chemical reaction has taken place?
That depends very much on what reaction is taking place. For some reactions a thermometer is all you need. For others, such as titrations, you need some sort of indicator, such as Eriochrome Black T. Other reactions may require a manner of collecting gas, still others, such a precipitation reactions, may only require your eyes.
What happens when both chemicals are alkaline?
Displacement may occur, or if both are made up in water, displacement reactions may occur between the ions of water and each chemical may occur
What is an another name for exothermic and for endothermic reactions?
it is a Many chemical reactions release energy in the form of heat, light, or sound. These are exothermic reactions. Exothermic reactions may occur spontaneously and result in higher randomness or entropy (ΔS > 0) of the system. They are denoted by a negative heat flow (heat is lost to the surroundings) and decrease in enthalpy (ΔH < 0). In the lab, exothermic reactions produce heat or may even be explosive. There are other chemical reactions that must absorb energy in order to proceed. These are endothermic reactions. Endothermic reactions cannot occur spontaneously. Work must be done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured during the reaction. Endothermic reactions are characterized by positive heat flow (into the reaction) and an increase in enthalpy (+ΔH).
What signs or indicators of chemical changes are shown in these reactions?
Chemical reactions can be obvious. First of all, listen: if you hear any sounds, such as a fizzing sound, that may be one indicator. Another is a change in color, or even state. If a solution is aqueous, and it precipitates (becomes a solid), that's also another indicator of a chemical reaction.
What results in a chemical change?
Chemical changes occur when a substance combines with another to form a new substance, called synthesis or, alternatively, decomposes into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. Some reactions produce heat and are called exothermicreactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. Understanding chemical changes is a major part of the science ofchemistry. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated. An example of a chemical change is the reaction between sodium and water to produce sodium hydroxide and hydrogen. So much energy is released that the hydrogen gas released spontaneously burns in the air.
What is the energy in gasoline called?
Thermochemical, as energy is released by the the chemical reactions between air and gasoline due to an igniting catalyst or heating (which may occur in different ways)
What happens to the composition of a substance during a chemical change?
Atoms are rearranged, heat may be given off, changes in color and odor might occur, or a gas or precipice may be formed. The composition is changed, and the above are signs of a chemical change.
What are some chemical reactions?
some chemical reactions take place when a chemical is added to a metal. sometimes the chemicl turns cloudy, it may fizz or a coat of black may appear on the piece of metal. hope this helps! :)
Is salt disolving in chemical change?
Dissolved sodium chloride may be involved in chemical reactions.
How are chemical reactions described?
Chemical reactions are described based on observations. It may be in terms of changes in color, state of matter, or density.
Which item is a sign of chemical change?
Signs of chemical reactions may be: - Gas release - Formation of a precipitate - Change of color - Change of odor - Change of pH - Change of aspect - Change of viscosity - Change of the temperature - Visible formation of new compounds.
How can you be certain that a chemical change has occurred?
Signs of chemical reactions may be: - Gas release - Formation of a precipitate - Change of color - Change of odor - Change of pH - Change of aspect - Change of viscosity - Change of the temperature - Visible formation of new compounds
How do you know if a chemical reactions has taken place?
Signs of chemical reactions may be: - Gas release - Formation of a precipitate - Change of color - Change of odor - Change of pH - Change of aspect - Change of viscosity - Change of the temperature - Visible formation of new compounds
