Ne is the molecule because the rest are mixtures
RADIATION. Radio waves, microwaves, IR, light, UV, x-rays, GAMMA waves etc are ALL Electromagnetic radiation. The difference between ALL the above is the frequency, I.E. The number of waves per second. The higher the frequency the more energy.
I know the first one is A
RMM of magnesium oxide=24+16=40
40g=1mol
therefore 62.5g will have =62.5/40=1.5625 moles
1.5 litres contain 1.5625 mols
therefore 1 litre =1*1.5625/1.5=1.042M
