<span>Physical change, heat caused this.
Water molecules that only vibrate are in solid form. If heat energy is added, the molecules will speed up their vibrations until they can break loose from the organized pattern of a solid and begin to slide over each other, changing to liquid state. If more heat energy is added, the molecules will speed up more and move randomly in all directions as a gas/vapor. Removing heat energy will reverse these changes.
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Answer:
The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms. This outermost shell is known as the valence shell, and the electrons found in it are called valence electrons.
Explanation:
First we have to understand what a half life is. A half life is a measure of time when the amount of a certain object is 50% of the original amount. Hence the answer for this is letter A. The initial amount is 100. fifty percent of 100 is 50 and that happens after 15 hours. Hence, 15 hours is the half life period.
Answer:
Absorb light energy
Explanation:
Chlorophyll absorbs light energy which is used to produce carbohydrate and oxygen in the presence of carbon dioxide and water.