Observation consists of receiving knowledge of the outside world through our senses,or recording information using scientific tools and instruments.Any data recorded during an experiment can be called and observation.
You should know that 1 mole has 6.02 x 10*23 atoms (Avogadro)...so if you have one atom with 4.48 *10-23 g...then 6.02 *10*23 how many??.. try the rule of 3...answer A is 26,9696 g. For answer b, first of all covert the 5000 kg to 5000000 g (you can write 5 x 10*6)..afterwards make the rule of 3.. if 26,9696 g they are in 1 mole, the mass of the plane 5 x 10*6 g... how many moles?.. be careful with g and the kg.!!.. Answer B should be 185393, 92 moles.
55.49 moles are in one kilogram of water...
