PLEASE HELP How many moles of helium gas are in 30.0L sample of He, if density of helium gas is 0.016 g/ml?

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)

Which diagram represents the phase tha occurs after a solid melts?

How is the use of hydroelectric power related to the sun