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The object has changed colors (for example, a lot of oxides are white; ferrous oxide is brown). Heat is another indicator of an exothermic chemical reaction. Warning: If the reaction results in pungent and/or colorful gaseous products, usually a harmful (unsafe to humans) reaction has occurred.
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Wiki User
∙ 14y ago
Wiki User
∙ 11y agoNot all of the following are discernable but they do occur:
Heat
gas bubbles
change of colour
condensation
change in volume
smell or taste change
physical and chemical property changes
altered conductivity
incandescence
boiling/melting point changed
Wiki User
∙ 12y ago- Usually a gas is evolved.
- Temperature changes, heat is either absorbed or evolved.
- It is usually irreversible.
- Change of state also occurs.
- A new product is formed which has the properties different from that of its constituents.
Wiki User
∙ 15y agoA substance changes into a different shape.
Wiki User
∙ 9y agoIt changes shape, new substances are formed, energy is used or given off or the last two?
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In examples of chemical changes the odor of sour milk indicates a chemical change has taken place true or false?
True
When paper turns yellow brown upon exposure to sunlight what type of change has taken place a chemical or physical change?
Physical, Because The Color Changes.. Not The Chemical Property Of The Paper.. :)
How can you be sure that at least one chemical change has occurred?
Evidence that a chemical reaction has taken place usually include appearance of a precipitate, change in color, or production of a gas.
What are not clues that a chemical reaction has taken place?
Phase changes are one example of a non chemical change. If the substance reacts the same way chemically, it has the same properties such as melting point, there has not been a chemical change.
A change in color when two solutions are mixed together is a clue that what has taken place?
A change in the color of a solution is a sign thatthere is a chemical change happening. A chemical change happens when two substances combine forming another substance. It can also happen when two or more substances decompose.
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.
In examples of chemical changes the odor of sour milk indicates a chemical change has taken place true or false?
True
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
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.
