The given question is incomplete. The complete question is:
The combustion of propane (C3H8) in the presence of excess oxygen yields 
and 
When only 2.5 mol of 
are consumed in order to complete the reaction, ________ mol of are produced.
Answer: Thus when 2.5 mol of are consumed in their reaction, 1.5 mol of are produced
Explanation:
The balanced chemical equation is:
According to stoichiometry :
5 moles of produce = 3 moles of
Thus 2.5 moles of will produce = 
moles of
Thus when 2.5 mol of are consumed in their reaction, 1.5 mol of are produced
N = ?
T = 449 K
V = 58.35 L
P =2.97
R = 0.082
Use the clapeyron equation:
P x V = n x R x T
2.97 x 58.35 = n x 0.082 x 449
173.2995 = n x 36.818
n = 173.2995 / 36.818
n = 4.70 moles
hope this helps!
Electric energy converted to light energy
PV / T = P'V' / T'
V = V'
P / T = P' / T'
P = 630 mmHg
T = 100 K
P' = 1760 mmHg
T' = ?
630 / 100 = 1760 / T'
T' = 1760 / 6,3
T' = 279,36 K
T' ≈ 280 K
A)3 bcuz paper filters are used to separate solids from liquids
b) 2 bcuz it is a process of separating a pure liquid from a mixture of other liquids.And it works when it has different boiling point
