Respuesta :
Hey there:
Given the reaction:
2 C2H2 + 5 O2 → 4 CO2 + 2 H2O
2 mol C2H2 ---------------- 5 mol O2
0.500 mol ---------------- moles O2 ??
moles O2 = 0.500 * 5 / 2
moles O2 = 2.5 / 2
=> 1.25 moles of O2
Molar mass O2 is 31.99 g/mol , so:
1 mol O2 -------------- 31.99 g
1.25 moles --------- mass O2 ??
mass O2 = 1.25 * 31.99 / 1
mass O2 = 40.0 / 1
mass O2 = 40.0 g
Answer C
Hope that helps!
Answer:
Option C
Explanation:
This is a problem of Stechiometry, so, to do this, let's write the equation again:
2C2H2 + 5O2 → 4CO2 + 2 H2O
According to the reaction, we can see that 2 moles of C2H" reacts with 5 moles of O2. So if we have 0.5 moles of C2H2, we only need to calculate the moles of O2 according to the above relation.
If: moles C2H2/moles O2 = 2/5
Then: 0.5 / moles O2 = 2/5
Solving for moles O2:
2 moles O2 = 5 * 0.5
moles O2 = 5 * 0.5 / 2
moles O2 = 1.25 moles
Now that we have the moles, we can calculate the grams, using the molecular weight of O2, which is 32 g/mol, then the mass:
m = moles O2 * MM
Replacing we have:
m = 1.25 * 32
m = 40 g O2
And this is the mass required to react exactly with the 0.5 moles of C2H2.
