Chemistry homework

Question

The method used by joesph priestly to produce oxygen made use of the thermal decomposition of mercury (II) oxide:

HgO(s)->Hg(l)+O2 (unbalanced)

calculate the volume of oxygen gas measured at 30.0 degrees Celsius and 725 torr that can be produced from complete decomposition of 6.67grams of mercury (II) oxide. Answer in L

Answer 1

2HgO(s) ==> 2Hg(l) + O₂ ... balanced equation

moles of mercury(II) oxide present = 6.67g x 1 mole/216.59g = 0.030796 moles

moles of O₂ gas that can be produced = 0.030796 moles HgO x 1 mol O₂/2 moles HgO = 0.015398 moles O₂

Using the ideal gas law PV = nRT, we can now solve for volume (V)...

Convert T (temp) to Kelvin: 30.0 C + 273 = 303 K

Convert torr to atm: 725 torr x 1 atm/760 torr = 0.954 atm

Solve for V:

V = nRT/P = (0.015398 mol)(0.0821 Latm/Kmol)(303K)/0.954 atm

V = 0.402 L (to 3 significant figures)