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Why does a colour change not always mean that a chemical change has taken place?
Wiki User
∙ 15y ago
The only example I can think of here is kind of weak; if you dissolve anhydrous copper sulfate in water, it turns blue. Evaporate the water completely, and you'll get the anhydrous copper sulfate back, and it won't be nearly as blue as the solution was.
Wiki User
∙ 15y ago
Wiki User
∙ 14y agoBecause color change can happen solely based on light refraction and have absolutely nothing to do with chemicals. Also, it may be due to simple mixing of colors (a red dye mixed with a blue dye gives purple, even without a chemical reaction), or (if the material is hot enough) due to black body radiation which is only dependent on temperature.
Wiki User
∙ 11y agoThere are a great many chemicals that are colorless, so chemical changes can and do take place which produce no change in color. One colorless chemical can be changed into another colorless chemical quite easily. If anything, this is the norm rather than the exception.
Wiki User
∙ 13y agoSome physical changes can cause a change in color as well. You can't conclude that a chemical reaction caused the color change.
For example, compressing an object tends to make objects darker or fuller in colour but does not chemically change them.
Wiki User
∙ 13y agobecause if you put food colring in water for example that doesnt mean its a chemical change
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What evidence do you have that a chemical reaction took place?
changes in its appearance ie colour and state
Is ice cream melting in a bowl a chemical change?
No. It is purely a physical change, that of melting. No chemical reaction takes place.
If you are trying to decide whether a chemical reaction does or does not take place when two substances are mixed what kind of evidence will you look for?
change of state change of colour fizzing/gas bubbles
What is always a characteristic of a chemical change but not always a characteristic of a physical change?
When a chemical change takes place, the chemical structure of particles involved changes (i.e. one or more new substances are formed). In a physical change, the physical state of the particles involved changes (e.g. a solid melts and becomes a liquid). The chemical structure of the particles does not change, and no new substance is formed.
What are three indicators of a chemical reaction occurring?
there are mainly two ways that indicate that a chemical change has taken place. These ways are the physical properties (the way things look, without changing the chemical makeup of a substance) are different, and the chemical properties (the way the substance reacts with other substances) are different.
What happens to make a chemical reaction?
In A Chemical Reaction the following take place a) there is evolution of a gas b) change in colour c) change in state d) change in temperature
What is an example of a color change that does not indicate a chemical reaction?
Many materials can change colour according to the temperature without there being any chemical reaction taking place.
Can a physical change always take place during a chemical reaction?
Yes
What evidence do you have that a chemical reaction took place?
changes in its appearance ie colour and state
What shows in reaction that chemical change has take place?
a reaction has taken place when one or more of the following occur : - a new substance is formed - change in colour - precipitate is formed
What makes a reaction to happen?
In A Chemical Reaction the following take place a) there is evolution of a gas b) change in colour c) change in state d) change in temperature
Is ice cream melting in a bowl a chemical change?
No. It is purely a physical change, that of melting. No chemical reaction takes place.
What energy transformation takes place when roasting a marshmallow?
1. Colour change 2. Odour produced (i believe) 3. Heat emitted
If you are trying to decide whether a chemical reaction does or does not take place when two substances are mixed what kind of evidence will you look for?
change of state change of colour fizzing/gas bubbles
What is always a characteristic of a chemical change but not always a characteristic of a physical change?
When a chemical change takes place, the chemical structure of particles involved changes (i.e. one or more new substances are formed). In a physical change, the physical state of the particles involved changes (e.g. a solid melts and becomes a liquid). The chemical structure of the particles does not change, and no new substance is formed.
What are three indicators of a chemical reaction occurring?
there are mainly two ways that indicate that a chemical change has taken place. These ways are the physical properties (the way things look, without changing the chemical makeup of a substance) are different, and the chemical properties (the way the substance reacts with other substances) are different.
Give three things you might see if a chemical reaction takes place?
There are many observations that may occur when a chemical reaction takes place. Some of the things are:- Change of colour, change of temperature change of state. These can be observed by the features below There might be a change in colour when mixing the reactants; the vessel in which the reaction is taking place might get warm on the outside or cold depending on the type of reaction. There may be effervescence or fizzing with gas production; a precipitate may form.
