Answer:

Explanation:
The final answer has a different set of units. In particular, meters (m) changes to centimeters (cm). To make this change, you need to multiply the first value by proportions.
When writing these proportions, it is important that they are arranged in a way that allows for the cancellation of units. For instance, since m is located in the denominator, it must be located in the numerator of the conversion.
<u>Proportion:</u>
1 m = 100 cm
The full expression:
<h3>

·

=

</h3><h2> ^</h2>
As you can see, the old unit (m) cancels out and you are left with cm in the denominator.
A. Decomposing water requires a high activation energy.
Explanation:
In decomposing water to release hydrogen gas to make fuel cells, the process requires a very high activation energy.
2H₂O ⇆ 2H₂ + O₂
This is the overall reaction. O-H must be broken to release free hydrogen to produce hydrogen gas.
The O-H bond is a very strong force of attraction that requires a high activation energy to overcome.
- The activation energy is the energy barrier that must be overcome before a reaction takes place.
- The sun is a renewable source of energy.
- Water decomposition produces useful oxygen gas needed by all life for cellular respiration.
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Answer:
the second one looks like it so I picked the second one
Rows of elements are called periods. The period number<span> of an element signifies the highest unexcited energy level for an electron in that element.
</span>Columns of elements help define element groups<span>. </span>Elements within a group share<span> several common properties. Groups are elements have the same outer electron arrangement.</span>
Answer:
6+9=15
mass number =15
mass number = no. protons + no. of neutrons