Question

3.A sample of a pure gas at 20 °C and 670 mm Hg occupies a volume of 562 cm³. How many moles of gas are in this sample?

4.An unknown compound contains only carbon and hydrogen. What is the volume (in L) of 1 mol of this gas at 100 °C and 760 mm Hg?

5.The same 1 mol sample of gas from the previous problem has a vapor density of 2.550 g/L. If the empirical formula of the compound is CH, what is the molecular formula for this compound?

Answer 1

Answer will be as follows-

o as equalion According to the ideal gas equation PV = nRT where for given problem P = Pressure of gas V = volume of gas na number of moles Ra Gas constant T₂ Temperature P = 670 mmHg = 670 atm 0 760 U= 562cm² = 5624 T= 20 12 293k R = 0.082 Latem / mokk Hence n= PV = 670 atm x 562 L 760 RT 1000 0.082 Latml x 293k en molk = 0.021 moles Answe