The fertilizer ammonium sulfate, (NH4)2SO4, is prepared by the reaction between ammonia (NH3) and sulfuric acid:
2NH3(g) + H2SO4(aq) → (NH4)2SO4(aq)
How many kilograms of NH3 are needed to produce 1.70 × 105 kg of (NH4)2SO4?
Enter your answer in scientific notation.