# Zena, warrior princess, had a rock with HgO in it. If she had 60 grams of Mercury after heating the rock, how many moles of HgO was in the rock?

May 28, 2018

Is it not spelled $\text{Xena}$...she was a fit girl, as I recall...

#### Explanation:

She got $60 \cdot g$ of mercury metal....this represents a molar quantity of $\frac{60 \cdot g}{200.6 \cdot g \cdot m o {l}^{-} 1} = 0.299 \cdot m o l$ with RESPECT to the metal. And thus there were $0.299 \cdot m o l$ with respect to mercuric oxide...

$H g O \left(s\right) + \Delta \rightarrow H g \left(l\right) + \frac{1}{2} {O}_{2}$

You have to heat the oxide fairly fiercley to effect the decomposition. the decomposition of $\text{cinnabar, mercuric sulfide}$, is much more facile.. What mass of $\text{mercuric oxide}$ was reacted here?

$H g S \left(s\right) + \Delta \rightarrow H g \left(l\right) + S \left(s\right)$