How many litres of ethyl mercaptan (C2H5SH ; liquid density = 0.8931 g/cm^3) should be added to 100,000 standard cubic meters of natural gas to produce a concentration in the gas of 1ppm?
other info
molar mass (C2H4SH) = 62 g/mol , (CH4 - natural gas) = 16 g/mol
1 standard m^3 = 1000L
1 mol = 22.4 L at STP (p = 1 atm, T = 273 K)