what are some signs that a chemical change has occurred

Chemical Reactions. … Reactions occur when two or more molecules interact and the molecules change. Bonds between atoms are broken and created to form new molecules. That’s it.

Which most likely indicates a chemical change has?

The following can indicate that a chemical change has taken place, although this evidence is not conclusive: Change of odor. Change of color (for example, silver to reddish-brown when iron rusts). Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat.

Which example indicates that a chemical change has occurred quizlet?

When two solutions are combined, they may form a solid substance. This solid substance is called a precipitate and indicates that a chemical change has occurred. For example when carbon dioxide is combined with aqueous calcium hydroxide (limewater), solid calcium carbonate (chalk) is formed as the precipitate.

Which most likely indicates a chemical change has occurred quizlet?

Suppose that a substance in a beaker is heated over a burner in a science lab. Which observation would most likely indicate that a chemical change has occurred in the substance? If the substance is a liquid or solid, production of an odor would indicate a chemical change.

What are the characteristics of the chemical changes give examples to elucidate any two characteristics Class 7?

Characteristics of a chemical change :

(1) One or more new substances are formed in a chemical change. (2) A chemical change is a permanent change. A chemical change usually cannot be reversed. (3) A lot of energy (in the form of heat, light, etc.) is either absorbed or given out in a chemical change.