True. Coastal regions are affected if it is warm currents over the ocean it make for a higher temperature over the land, if it's a colder current over the ocean it makes for temperatures to drop over land. This happens when the wind blows in from the sea.
1- One mole is = 6.02 x 10^23 of anything, So one mole of atoms is 6.02x10^23.
2- when the balloon contains 0.15 moles of Co2 gas so:
the no.of molecules of Co2 = 0.15 x 6.02x 10^23
= 9.0 x 10^22