- #1
cherrymilk
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Homework Statement
Ti-6Al-4V is a metal alloy used to make biomaterials. Its composition is 90% Ti; 6% Al and 4% V (mass percentages).
(a) What are the mass fractions of Ti, Al and V?
(b) What are the mole fractions of Ti, Al and V?
Homework Equations
Mass fraction = m/mtotal
Mole fraction = n/ntotal
The Attempt at a Solution
The first thing I did was find the molar mass of Ti-6Al-4V, which came out to be 413.527g. Then, using this information, I found the masses of Ti, Al and V using the following method:
Mass of Ti: (90%)(413.527) = 372.174g
Mass of Al: (6%)(413.527) = 24.812g
Mass of V: (4%)(413.527) = 16.541g
I then started to find the mass fractions by dividing the masses I had found by the molar mass like so:
Mass fraction of Ti: (327.174)/(413.527) = 0.9
I found the mass fractions of Al and of V in a similar fashion, getting 0.06 and 0.04 respectively.
My question is: was this the correct approach to the problem? When I started part (b), I realized that the 'mass fractions' I had found in part (a) used the equation n = m/M and that's why I'm a bit confused. Say that 0.9 is the number of moles of Ti, 0.06 is the number of moles of Al and 0.04 is the number of moles of V, that would yield a total number of 1, meaning that the mass and mole fractions would be equal, which doesn't make much sense to me.
Any help would be much appreciated!