francium , in the Periodic table the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. making helium is the smallest element, and francium the largest.

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3 years ago

Help pls , question is in picture

Nata [24]

Explanation:

IM PRETTY SURE IT IS D !! IF ITS WRONG IM SORRY THAT WHAT

I GOT

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3 years ago

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A vessel of volume 100ml contains 10% of oxygen and 90% of an unknown gas. The gases diffuses in 86 second through a small hole

swat32

The molecular weight of unknown gas : 23.46 g/mol

<h3>Further explanation</h3>

Given

A vessel contains 10% of oxygen and 90% of an unknown gas.

diffuses rate of mixed gas = 86 s

diffuses rate of O₂ = 75 s

Required

the molecular weight of unknown gas (M)

Solution

The molecular weight of mixed gas :(M O₂=32 g/mol)

$\tt 0.1\times 32+0.9\times M=3.2+0.9M$

Graham's Law :

$\tt \dfrac{r_{O_2}}{r_{mixed~gas}}=\sqrt{\dfrac{M_{mixed}}{M_{O_2}} }\\\\\dfrac{75}{86}=\sqrt{\dfrac{3.2+0.9M}{32} }\\\\0.76=\dfrac{3.2+0.9M}{32}\\\\24.32=3.2+0.9M\\\\21.12=0.9M\rightarrow M=23.46~g/mol$

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3 years ago