Answer:
B There are two grams of hydrogen for each gram of carbon in this compound.
Explanation:
The second option is a wrong interpretation of this chemical representation of formaldehyde.
Formaldehyde is an organic compound with the formula CH₂O.
As this is the simplest formula of the compound, it is the empirical formula. Also, the formula is the actual one for the compound and it is the molecular formula.
Chemically, the formula shows 1 mole of carbon, 2 moles of H and 1 mole of oxygen in the compound.
- A mole of a substance is more a less a unit of measurement in chemistry and it is the amount of substance that contains the avogadro's number of particles.
This ratio is not the mass of chemical species in the compound. You cannot tell the mass of elements in a compound by merely looking at the formula.
Since Methane is assumed an ideal gas, we need to know its moles in each streams.
Therefore, we can use the ideal gas law to find the mole in the container by:
P V=nRT ⇒ n=PV/R T
n=no of moles of the gas = mass/molar mass
Molar mass o f CO2=44g/mol, mass = 44g
P= 25bar = 101000X25Pa=2.5x106Pa
V = 20L = 20dm3 = 0.02m3
T=100C=373K
R=8.314J/mol.K
n1= 2.5x106Pa x 0.02m3 / 8.314J/mol.K x 373K
n1 = 16.1mols
Similarly for stream 2, we have n2 which is
P=1bar = 100000Pa
T= 100C= 373K
V=200L = 0.02m3
n2= 1x105Pa x 0.02m3 / 8.314J/mol.K x 373K
n1 = 0.645mol
So the new stream is an addition of these two streams of methane which has
n3 = n1 + n2 =16.75mols of methane
T=?
V=200L=0.02m3
P = 25Bar = 2.5x106Pa
T= PV/nR
T = 2.5x106Pa x 0.02m3 / 16.75 x 8.314
T=359K
So the final temperature of the gas in the tank is 359K
