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What is the only way to confirm that a chemical change has taken place?
Wiki User
∙ 8y ago
To be certain that a chemical change has taken place you check the composition of the sample before and after the change. The following is a chemical property of water at 4 C is its ability to decompose into hydrogen and oxygen.
Wiki User
∙ 9y ago
Wiki User
∙ 11y agoA new substance must occur.
However, there are many hints that show that a chemical might have taken place:
- a change of color
- possible release of a gas
- a precipitate
- variation of pH
- variation of temperature
- variation of viscosity
- a specific smell
Wiki User
∙ 8y agoThe most important is the formation of new compounds.
But also:
Some indicators of a chemical reaction are:
- change of color
- change of odor
- release of a gas
- change of the temperature
- change of the viscosity
- formation of a precipitate
- change of general appearance
- possible explosion
- possible chemiluminescence
Wiki User
∙ 7y agoSome 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
∙ 15y agoDemonstrate that a release of energy occurred after the change.
Wiki User
∙ 12y agoThe only way to be sure a chemical reaction or change has occurred is to test the composition of a sample before and after a change.
Wiki User
∙ 12y agoenergy has been used or given out
Anonymous
You can tell that a new stubstance has formed
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What does the word physical change mean?
A physical change means that only the appearance of the substance has changed. So if your tear up a piece of paper, its still paper so a physical change has taken place. If you heat or freeze water its only a change of state so its still a physical change. So long as the molecular or chemical structure of the atom/substance does not change it will always be a chemical change. H20 will always be H20.
Is mixing lemonade powder into water a chemical or physical change?
Mixing lemonade powder into water is a chemical change. This is because the powder changes the water molecules and can not be taken out.
Is breaking a glass window with a baseball a chemical change or physical change?
Breaking, grinding, cracking are all examples of a physical change. The nature of the substance has not changed, just the size of the pieces has changed.
What type of change that produces a new substance?
If you mean changing one element into another, like uranium 238 into plutonium 239, which happens in nuclear reactors, the word is 'transmutation'. Otherwise many chemical reactions form new substances, without the elements involved changing, and these would be called 'chemical reactions'.
During a chemical or physical change energy may be?
Vaporization is an endothermic process; evaporation is exothermic.
What identifies a chemical change has taken place?
Signs that a chemical change has taken place include the formation of a gas, the formation of a precipitate, a change in temperature, and a change in color.
What is rusting mean?
A chemical change has taken place
What evidence is there to show that a chemical reaction has taken place when an egg is cooked?
The change in color indicates that a chemical reaction has taken place.
Is corrosion of aluminium metal a physical change or a chemical change?
It is a chemical change. Through corrosion, a chemical reaction has taken place.
When liquid water evaporates which has taken place molecular change or chemical change?
Physical change.
What does not indcate that a chemical change may have taken place?
Fracture formation
How do you know when a chemical change has taken place when a firework goes off?
youwill hear it
2 colorless liquids produce a white precipitate when they are mixed together is it a chemical change or a physical change?
Chemical change. The formation of a precipitate is one indication that a chemical reaction has taken place.
What is making salt water to gargle for a sore throat a physical or chemical change?
Physical. It is a mixture of salt and water. No chemical change has taken place.
Why is adding drink powder to water is chemical change?
No. If you evaporate the water, the drink powder is left behind. No chemical change has taken place.
What evidence demonstrates that a chemical change has taken place?
You might observe a change in color, gas bubbles being formed, a change in temperature (this might require the use of a thermometer, unless the solution actually boils), or you can test for a specific chemical by using an indicator, or analyse the solution by means of a mass spectrometer. Explosions are also a very convincing form of evidence that a chemical change has taken place.
In examples of chemical changes the odor of sour milk indicates a chemical change has taken place true or false?
True
