Answer:
Fe: 23.1%
N: 17.4%
O: 59.5%
Explanation:
You take the grams that each weigh on the periodic table and add it all up. Afterward you create fractions of each over the whole. (Example: Fe/Fe+N+O) then you divide and turn that decimal into a percentage.
Answer:
b. It exists in three different states at normal conditions in the Earth's atmosphere
Explanation:=
Snow, rain and water vapour can exist at normal conditions in the Earth's atmosphere.
a. is wrong. Only hydrogen and helium can escape Earth's atmosphere in significant amounts.
c. is wrong. The molecules of every substance are in motion even when it is solid.
d. is wrong. Other substances can form from a wide range of chemical processes.
e. is wrong. All substances expand when they become a gas.
They did not repeat their tests multiple times.
Reason being is using the same stopwatch doesn’t matter and changing the reactants won’t help, and you without a doubt need more than one person collecting the data so,
They did not repeat their tests multiple times is the answer.
It releases energy (what I am saying in other words that "D. Releases" would be your answer)