So the equation is,
2Cl2(g) + 7O2(g) + 130kcal -> 2Cl2O7(g)
from this , ΔH°rxn=
is mentioned because it is for per mole of reaction. So for 4. moles of the product
we need 4/2 moles of reaction to be used to calculate associated enthalphy change for the reaction.
Therefore
<u>Answer:</u> 55.7 moles of
are needed to produce the given amount of 
<u>Explanation:</u>
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
The equation used is:
......(1)
Given values:
Moles of
= 55.7 moles
The chemical equation for the decomposition of water follows:

By the stoichiometry of the reaction:
If 2 moles of hydrogen gas is produced from 2 moles of water
So, 55.7 moles of hydrogen gas will be produced by =
of water
Hence, 55.7 moles of
are needed to produce the given amount of 
The answer should be 2.4 meters.
Answer:
The radius of the centrifuge.
Explanation:
Hello,
Since the radius of the centrifuge is just a design parameter, it wouldn't be a cause of failure because it is used to know how many tubes could be fitted in into the centrifuge. On the other hand, keeping you attention away from other factors could turn into a failure as long as the sample could be poured down or just turn out inadequate for the expected results.
Best regards.