Steam that is used to heat a batch reaction vessel enters the steam chest, which is segregated from the reactants, at 250 C saturated and is completely condensed. The reaction absorbs 2300 kJ/(kg of material) in the reactor. Heat loss from the steam chest to the surroundings is 1.5 kJ/s. The reactants ate placed in the vessel at 20 C, and at the end of reaction the material is at 100 C. If the charge consists of 150 kg of material and both products and reactants have an average heat capacity of Cp=3.26 J/(gK), how many kilograms of steam are needed per kg of charge? The charge remains in the reaction vessel for 1 hr