Answer:
a. Oxygen is the limiting reagent. 
b.
%
Explanation:
Hello,
a. Limiting reagent and sulfur trioxide's theoretical yield.
At first, we must compute the involved moles for both sulfur dioxide's and oxygen's as follows, considering the volumes in liters and the pressure in atm of 50.0mmHg*1atm/760mmHg=0.0658atm:

Afterwards, by considering the properly balanced chemical reaction:

We compute the oxygen's moles that completely reacts with the previously computed
moles of
as follows:

That result let us know that the oxygen is the limiting reagent since just
moles are available in comparison with the
moles that completely would react with
moles of
.
Now, to compute the theoretical yield of sulfur trioxide, we apply the following stoichiometric relationship:

b. Percent yield.
At first, we must compute the collected (real) moles of sulfur trioxide:

Finally, we compute the percent yield:
%
%
%
Best regards.
I think it’s SO3 I’m not quite sure though
Answer:
A planet is believed to form when the mutual gravitational attraction of debris orbiting a star accumulates into a growing mass.
Explanation:
Planetary rings, then, consist of millions of separate small rock and ice particles, each maintaining their own orbit around the host planet.
Answer:
95.211 g/mol
Explanation:
For example magensium chloride has the formula unit MgCl2 , i..e., for every magnesium cation there are two chloride anions in the crystal. Or, we would say that the formula weight of MgCl2 = 95.211 g/mol.
Answer:
boron compound - known as Borax
Explanation: