Question

When the reddish-brown mercury(ii) oxide (hgo) is heated, it decomposes to its elements, liquid mercury metal and oxygen gas. if 1.19 g hgo is decomposed to hg, calculate the mass of the pure hg metal produced. 2 hgo(s) 2 hg(l) + o2(g)?

Answer 1

2HgO----->  2Hg  +  O2

find  the  moles  of  HgO,

moles=mass/molar  mass

1.19g/216.59(molar  mass  of  HgO) =   5.49  x10^-3moles

by  use   of  mole  ratio  between  HgO  and Hg  which  is  2:2    or  1:1  the moles   of  Hg  is  also   5.49  x10^-3  moles

mass  of  Hg  is  therefore  =  (5.49  x10^-3)  x  200.59  =  1.101  grams