Question

Choose all the answers that apply. Which of the following usually indicates a chemical reaction? gas bubbles color change increase in temperature decrease in temperature release of light energy

Answer 1

All options are correct.

Step-by-step explanation:

A chemical transformation or phenomenon occurs when the nature or composition of matter changes. In this case, the initial particles (which may be molecules, atoms, ionic clusters, ions, etc.) are sort of disassembled and their atoms rearrange, assembling new molecules, clusters, atoms, ions, etc., that is, new substances. This is a chemical reaction.

As the chemical reaction causes the transformation of matter, it is possible to visualize some changes in certain characteristics of matter. The changes I indicate that a chemical reaction is happening are:

• gas bubbles
• color change
• increase in temperature
• decrease in temperature
• release of light energy

Answer 2

All the choices given are correct

• gas bubbles
• color change
• increase in temperature
• decrease in temperature
• release of light energy

Step-by-step explanation:

• Chemical reactions occurs when elements or compounds chemically join to form other compounds.

But, how do we know that indeed a chemical reaction has occurred?

• Chemical reactions involve changes of different parameters when they occur, thus various indications are used to show the occurrence of chemical reactions.

These indications include;

• Gas bubbles, also known as effervescence, for example when sodium metal is mixed with an acid, gas bubbles will be produced showing occurrence of a chemical reaction.
• Color change, which shows the formation of a new substance.
• Increase in temperature, which occurs in endothermic reactions where heat is absorbed from the surroundings.
• Decrease in temperature, which occurs in exothermic reaction where heat is lost to the surroundings.
• Other indicators include, formation of a precipitate, production of light, etc.