Answer:
1.15 atm
Explanation:
According to Dalton's law of partial pressures, the total pressure is the sum of all the partial pressures of the gases present in the mixture.
Therefore we have:
Total pressure = partial pressure of carbon monoxide + partial pressure of oxygen + partial pressure of carbon dioxide
We were given the following:
Total pressure = 2.45 atm
Pressure of oxygen = 0.65 atm
Pressure of carbon monoxide = x
Pressure of carbon dioxide = 0.65 atm
Therefore:
2.45 = x + 0.65 + 0.65
2.45 = x + 1.3
x = 2.45 - 1.3
x = 1.15 atm
and 
.
Assuming complete decomposition of both samples,
First compound:
; 
of the first compound would contain
Oxygen and mercury atoms seemingly exist in the first compound at a 
ratio; thus the empirical formula for this compound would be where the subscript "1" is omitted.
Similarly, for the second compound
; 
of the first compound would contain
and therefore the empirical formula
.
Mendeleev arranged the elements according to their atomic masses
