Heyy, I have a quick question. I am doing binary systems, and I have a water/propanol system, and it says " 0.433 mole fraction propanol (71.7% propanol by weight)" does this mean that the mole fraction of water is 0.433 or propanol? Cause if propanol is 71.7% then wouldn't it be the bigger fraction, and if Xprop + Xwater = 1 then then other fraction would be 0.567 and wouldn't that be bigger?
If it says 0.433 mol fraction of propanol then that must be what it is. The mole fraction of water will be 1.000 - 0.433 = ??
Remember that propanol has a molar mass much larger than that of water and mol fraction is [mols Prop/(mols Prop + mols H2O)]. You might want to do a quick calculation, to satisfy your curiosity, that 71.7 g prop + 28.3 g water gives a mol fraction of 0.433.
Good question! In a binary mixture, the mole fraction of each component represents the proportion of that component in the mixture. The mole fractions always add up to 1, so if one component has a mole fraction of 0.433, the other component would have a mole fraction of 1 - 0.433, which is approximately 0.567 in this case.
Now, regarding the percentage by weight, it tells you the mass proportion of each component in the mixture. In this case, it indicates that the propanol makes up 71.7% of the total mass of the mixture, while the remaining 28.3% is water.
It's important to note that mole fraction and weight percent represent different properties of a mixture. The mole fraction is related to the number of moles of each component, while the weight percent is related to the mass of each component. So, they are not directly comparable.
To summarize, in your water/propanol system:
- The mole fraction of propanol is 0.433.
- The mole fraction of water is 1 - 0.433 = 0.567.
- The propanol component represents 71.7% of the mixture by weight.
- The water component represents the remaining 28.3% of the mixture by weight.