2 A student carried out an experiment to measure the percentage oxygen in the air by using the rusting of iron. The experimental set-up is shown below,
The initial reading on the measuring cylinder was 95 cm, They let the
apparatus for 2 days and the new reading on the measuring cylinder was
80 cm
-iron filings
-measuring cylinder
air
-water
90
100
a Calculate the percentage oxygen in the air using this data.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

it would be d. henry moseley

hope this !

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