Question

For the reaction 2C8H18+ 250₂ 16CO₂ + 18 H₂O a) find the volume (L) of Oz gos @ Şte needed for the complete combustion of 10.0g of Coltis (4. 6) find the volume of O2 gas if the tempeture is 35.0° C and pressure is Hg 845 mm o

Answer 1

Answer:

Given that, a combustion reaction is 2 C8H18 + 25 O2 $\rightarrow$ 16 CO2 + 18 H2O.

a) We have to calculate the volume of O2 in L is needed at STP for the complete combustion of 10.0 g of C8H18.

So, at the STP, the temperature is T = 273 K and the pressure is P = 1 atm.

The molar mass of C8H18 is 114 g/mol.

So, 10.0 g of C8H18 is = (10/114) moles = 0.0877 moles C8H18.

So, 2 moles C8H18 reacts with 25 moles of O2.

Thus, 0.0877 moles C8H18 reacts with = (25*0.0877/2) moles = 1.09625 moles of O2.

We know that, PV = nRT, where R is gas constant = 0.082 L.atm.mol-1.K-1.

or, V = nRT/P = [(1.09625 mole)*(0.082 L.atm.mol-1.K-1)*(273K)/(1 atm)] = 24.54 L.

So, the required volume of O2 (g) at STP is 24.54 L.

b) We also find the volume in L when T = 35oC = (35+273) K = 308 K and P = 845 mm Hg = (845/760) atm = 1.112 atm.

We know that, PV = nRT

or, V = nRT/P = [(1.09625 mole)*(0.082 L.atm.mol-1.K-1)*(308 K)/(1.112 atm)] = 24.90 L.

Hence, the required volume is 24.90 L.