Problem
First, let's consider the preburner on the HPFTP. LH2 enters the preburner at 35.2 kg/s, and LO2 enters the preburner at 30.3 kg/s. Use the overall H2-O2 stoichiometric reaction to determine the mass flow rate of LH2 that is needed to completely consume the 30.3 kg/s of oxygen entering the preburner. Then use this to write the overall stoichiometric reaction for the fuel-rich preburner, and from the resulting product composition determine the mass fractions of the product species in the product composition.