## How many grams are there in 2 x 1024 molecules of BCl3?

Question

How many grams are there in 2 x 1024 molecules of BCl3?

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3 years 2021-08-28T16:56:34+00:00 1 Answers 7 views 0

How many grams are there in 1×10^24 molecules of BCl3? I use 117.17 as the molecular weight.

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How many grams are there in 1×10^24 molecules of BCl3? I use 117.17 as the molecular weight.

Did you try approaching this problem with dimensional analysis?

We know:

1×1024 molecules

117.17 g/mol

And we want our answer to be in g.

molecules ×gmol×“conversion factor”=g

The conversion factor has to have units of

molmolecules in order for everything to work out.

What property do you know that has units of molmolecules?

I don’t know of any, but I do know that Avogadro’s number has units of moleculesmol. So for our conversion factor, we divide by Avogadro’s number, which is the same thing as multiplying by its inverse.

1×1024 molecules×117.17 gmol×mol6.022×1023molecules=

The “molecules” units cancel. The “mol” units cancel. Leaving us with “g”. The dimensions (units) work out. Now just do the math with the numbers.

Explanation: