The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the surface, probably by the use of a bleaching agent.
You're off to a good start, now find the mass of H2O and put it under I mol,
then multiply 1 mol over the mass of H2O by 215 grams
D, <span>Monotonic gases, which have no inter molecular attractions are most suited as ideal gases </span><span />
1 km is equal to 100,000 cm

and you need to divide it to 1 km so that you can get rid of the km.