Answer:

Explanation:
Hello.
In this case, given the formula:

Whereas E is the energy, h the Planck's constant and u the frequency of the photon. Thus, solving for it, we obtain:

Or also:

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Answer: Because hydrogen is a gas.
Explanation: If children were running around with balloons filled with hydrogen gas, then they would catch fire. So the answer to your question is, its simply dangerous.
Answer: C. CO₂ and H₂O
Explanation:
Combustion reactions produce carbon dioxide and water.