How many atoms are in 2 moles of oxygen?

Concerning the 10.0 ml of 0.50 m nacl to 100 ml of solution: when a solution is diluted, does it change the number of moles dissolved?

Aroller coaster car is traveling down a track at 22 m/s. the car has a mass of 2000 kg. what is the kinetic energy of the car? a) 22,000 j b) 968,000 j c) 484,000 j d) 44,000 j

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3 -> a2cr(no3)3 + a3ag2so4