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
- formation of new compounds
i was born
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she dissapeared
what hapened
Hernán Cortés happened.
slavery
It was 2001, because 911 hapened.
it hapened in 2013
The confederation hapened on the first of July,1867.
M. Emy
Pompeii was overwhelmed in 79AD by the lava flows from the volcano Vesuvius.
what will be hapened if soundness and fineness more or less percentage presence in cement.