# need help with my chem homework?

The questions is: oxygen (O2) was first isolated by the decomposition of Mercury (II) oxide (HgO) into mercury and oxygen. If 58.67g of mercury(II) oxide were completely decomposed to generate 54.34g of mercury, how many grams of oxygen should have been produced? Please show the work on how to do it, I need to learn thank you

Relevance

Oxygen from HgO.....

2HgO(g) --> 2Hg(l) + O2(g)

58.67g ...... (54.34g)...?g

58.67g HgO x (1 mol HgO / 216.59 g HgO) x (1 mol Hg / 1 mol HgO) x (200.59g Hg / 1 mol Hg) = 54.34g Hg ............ just checking to see if the mass of Hg is consistent with 100% yield of oxygen

Repeat the calculation, except solve for oxygen.

58.67g HgO x (1 mol HgO / 216.59 g HgO) x (1 mol O2 / 2 mol HgO) x (32.0g O2 / 1 mol O2) = 4.33g O2

Here's a newsflash.  If you know the mass of the reactants, then the mass of the products must equal it. It's called the "law of conservation of mass." Therefore, you could just as easily have subtracted to get the mass of oxygen:

58.67g - 54.34g = 4.33g O2

• Kaitlyn4 weeks agoReport

Thank you, it is my first year taking chemistry and I appreciate your help!

• Next time u have diarrhea, p*ss and sht in a glass then take it to class. Tell the teacher it’s just chemicals

• Completely decomposed - means ALL was decomposed

58.67 - 54.34 = 4.33 g Oxygen should have been formed