How many moles of FeS2 are needed to produce 27.5 moles of Fe2O3

Which of the following would have less momentum than a 52 kg cheetah running at 10 m/s?

Nitrogen dioxide decomposes according to the reaction 2 no2(g) ⇌ 2 no(g) + o2(g) where kp = 4.48 × 10−13 at a certain temperature. if 0.70 atm of no2 is added to a container and allowed to come to equilibrium, what are the equilibrium partial pressures of no(g) and o2(g)

What is the value of the standard enthalpy of formation of an element in its most stable form?