Answer:
the catalyst is the two gray dots
Answer:it all above
Explanation:
it all above because all the answer are truth so it all above
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.
8.9 g + 90 g = 98.9 Copper has a density