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What should not be used to indicate a chemical reaction?
Change of shape can not be used to indicate a chemical reaction has happened. Examples of evidence of a chemical reaction are changes in odor or color.
Which observation does not indicate that a chemical reaction has occured?
A change in state, such as boiling or melting, does not always indicate a chemical reaction has occurred. It could be a physical change.
What change undergoes chemical change?
For example a chemical reaction with an alkali metal.
Is milk sours a example of physical change?
No, milk souring is an example of a chemical change. When milk sours, bacteria ferment the lactose in the milk, producing lactic acid, which changes the composition and properties of the milk. This is a chemical reaction, not a physical change.
Why does a change in temperature indicate that a chemical reaction may occur?
Because a chemical reaction has different sign's. And heat is one. But if the temperature is dropping then it is not going through a chemical change.
Is heat light and change in odor indicate a physical change?
Heat, light, and change in odor can indicate a physical change depending on the context. For example, melting ice into water is a physical change because it does not alter the chemical composition of the substance. However, if a substance undergoes a chemical reaction that results in heat, light, and change in odor, then it would be considered a chemical change.
What are four things that indicate that a chemical change may have taken place?
Change in color: If the substance changes color during a reaction, it may indicate a chemical change. Formation of gas: Production of gas bubbles, fizzing, or bubbling is a sign of a chemical change. Temperature change: Significant heat or cooling effects can indicate a chemical reaction is occurring. Formation of a precipitate: When a solid substance forms in a solution, it suggests a chemical change has taken place.
A chemical reaction causes a chemical change true or false?
It is true that a chemical reaction causes a chemical change. An example of this can be seen by adding baking soda to vinegar.
Is fizzing is an example of physical change?
Fizzing is the result of a chemical change - a chemical reaction with gas releasing.
Is rust an example of a physical change or a chemical change?
It is an example of chemical change which cannot be reversed. In this change, Iron oxidizes under the presence of oxygen and moisture. The reaction is called a reduction-oxidation, or redox, reaction.
How might a thermometer help you decide if there was any chemical change on mixing iron and charcoal?
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.
Is rust an example of a chemical change?
No, rusting is a chemical reaction in which iron reacts with oxygen in the presence of water to form iron oxide. This process is an example of a chemical change where the substance's chemical composition is altered.
