Answer:
d. 127 g/mol.
Explanation:
Hello!
In this case, since we have the amount of molecules of this this compound, we are able to compute the moles out there by using the Avogadro's number:

Which correspond to the moles of X2. Then, by using the mass we are able to compute the molar mass of X2:

It means that the atomic mass of X halves the molar mass of X2, which is then d. 127 g/mol.
Best regards!
HI
So, the formula for water is H2O
When you have the same amount of the reactants , hydrogen will be the limiting reactant.
Limiting reactant is the thing that runs out first.
Answer: 0.0 grams
Explanation:
To calculate the moles, we use the equation:

a) moles of butane

b) moles of oxygen


According to stoichiometry :
2 moles of butane require 13 moles of 
Thus 0.09 moles of butane will require =
of 
Butane is the limiting reagent as it limits the formation of product and oxygen is present in excess as (1.02-0.585)=0.435 moles will be left.
Thus all the butane will be consumed and 0.0 grams of butane will be left.
The two compounds shown indeed have tha same molecular formula, C5 H11 NO2. One of the molecules has a group NH2 and a group COOH, the other molecule has a NOO group, that makes that the two isomers have a completely different structure, with the atoms arranged in a completely different order. <span>This kind of isomers fits in the definition of structural isomers, so the answer is structural isomers.</span>