a) What volume of dry carbon dioxide, measured at 25 degrees celcius and 785 mm Hg, will result from the complete combustion of 2.50g of pentane?
b) The complete combustion of 5.00g of pentane releases 243 kJ of heat. On the basis of this information, calculate the value of Delta H for the complete combustion of one mole of pentane.
c) Under identical conditions, a sample of an unknown gas effuses into a vacuum at twice the rate that a sample of pentane gas effuses. Calculate the molar mass of the unknown gas.
*Pentane is C5H12 with #'s in subscripts. Pentane's molar mass is 72.15g.
Give answers and HOW to get the answers.
2007-01-22 19:52:45 · 1 answers · asked by Ichigo204 3 in Science & Mathematics ➔ Chemistry
The reaction is
C5H12 + 8O2 -> 5CO2 + 6H2O
a) Moles of C5H12 = 2.5/72.15
Moles of CO2 = 5x2.5/72.15
Vol of CO2 = (0.0821x298x5x2.5x760)/(785x72.15) = 4.104 litres
b) Delta H = 243x72.15/5 = 3506.49 kJ
c) Molar mass of gas = 72.15/4 = 18.04 g
2007-01-23 03:38:51 · answer #1 · answered by ag_iitkgp 7 · 0⤊ 0⤋