C’est un On dispose d'un échantillon de
8
,
7
4
×
1
0
−
1
m
o
l
8,74×10
−1
mol de molécules d'eau (
H
2
O
H
2
O).
On donne :
N
A
=
6
,
0
2
×
1
0
2
3
m
o
l
−
1
N
A
=6,02×10
23
mol
−1


Déterminer le nombre de molécules d'eau de cet échantillon.

On donnera un résultat avec 3 chiffres significatifs.

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

The air in an automobile tire with a volume of 2.60 ft3 is at 70°f and 21 psig. determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. assume the atmospheric pressure to be 14.6 psia and the temperature and the volume to remain constant. the gas constant of air is ru = 53.34ft⋅lbflbm⋅r(1 psia144 lbf/ft2) = 0.3704 psia⋅ft3lbm⋅r the amount of air that must be added to raise the pressure is lbm

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