# How many moles of disulfur decafluoride are present in 1.55*10^22 molecules of this compound?

Sep 5, 2016

Approx. $0.025 \cdot m o l$

#### Explanation:

There are $6.022 \times {10}^{23}$ ${S}_{2} {F}_{10}$ units in one mole of the stuff by definition.

And thus $\left(1.55 \times {10}^{22} {\text{ molecules")/(6.022xx10^23" molecules mol}}^{-} 1\right)$ $\cong$ $0.025 \cdot m o l$

${S}_{2} {F}_{10}$ is nasty stuff, though apparently it is quite odourless (this is a "good" property in a war gas, because some punter might get a lethal dose of it before he realizes he has been gassed; the substance has never been deployed in war).

Note that in this problem we could substitute any formula in the equation, and get the molar quantity.