[peterschmidt3943]

30 cm3 of xenon are mixed with 20 cm3 of fluorine. The gases react according to
the following equation.
Xe(g) + F2(g) → XeF2(g)
Assume that the temperature and pressure remain constant.
What is the final volume of gas after the reaction is complete?

I have a problem with this question. We know that 20cm^3 react with 30cm^3. But does that mean that 20cm^3 react ? Because we got 2*F, we got 10cm^3 of fluorine reacting with 10cm^3 with Xe, right ?

[Borek]

Do you know what the limiting reagent is?

[peterschmidt3943]

yes, I do. In this case, F is the limiting reactant, right?

[peterschmidt3943]

and since F is the limiting reactant, we got 20 cm^2 used up, leaving 10cm^2. But since we produced 20cm^2, we got in total 30cm^2 left , right ? If yes, i do not know why we have to calculate everything with the values from the limiting reactant. Why does one mole of the limiting reactant equal 1 mole of Xe, or XeFe2 ?


Kind regards

[Borek]

First of all - no, we don't work with square centimeters, we work with volume, not surface. But I assume it is just a typo.

we got 20 cm^2 used up

20 mL of what?

leaving 10cm^2

10 mL of what?

But since we produced 20cm^2

20 mL of what?

we got in total 30cm^2 left , right ?

30 mL of what?

[peterschmidt3943]

20ml of F
leaving 10ml of Xe
20ml of XeF2
total gas amount left in the syringe: 30ml
respectively...

[Borek]

Looks OK.

[peterschmidt3943]

Yes, but why do we claculate with the values from the limiting reagant?

[Borek]

Because one of the reagents limits the reaction. I will rephrase my question: do you understand what the limiting reagent is?

[Enthalpy]

Citing https://en.wikipedia.org/wiki/Xenon_difluoride

Xenon difluoride is a dense, white crystalline solid.
It has a low vapor pressure.
Vapor pressure    6.0×10² Pa
Melting point    128.6 °C (no boiling point given)

In addition, the reaction needs conditions that decompose the product too, so can the reaction be complete?

Looks like the question's conditions are strongly idealized.

[sjb]

Citing https://en.wikipedia.org/wiki/Xenon_difluoride...

True but I don't think this is quite relevant to the actual question?

[Enthalpy]

Because students keep in mind for decades some claims and assumptions of their assignments, these should be correct. And it is important to debunk them when wrong.