How would you solve these Chemistry problems?

J

Jessica

New member
1) PF3 reacts with XeF4 to give PF5.

2 PF3(g) + XeF4(s) --> 2 PF5(g) + Xe(g)

How many moles of PF5 can be produced from 94.2 g of PF3 and 47.1 g of XeF4?

I'm not really sure how to approach the problem... I tried to convert grams to moles and then moles to moles and then added the PF3 and XeF4 together but I don't think that's the right way to do the problem.

2.) The thermite reaction, used to weld rails together in the building of railroads, is described by the following equation:

Fe2O3(s) + 2 Al(s) --> Al2O3(s) + 2 Fe(l)

Calculate the mass of iron metal that can be prepared from 158 grams of aluminum and 263.3 grams of iron(III) oxide.

I tried doing the same thing with this one but when I submit my answer, it tells me it's incorrect.

If you could help me out on these, it would be very helpful!
 
well the first question.. It doesnt tell you.. But its a limiting reactant question...
anything you have two quantities like that. you should note that right awayyyy

anyways,
so you will start with 94.2 g PF3 and convert that to PF5
and start another 47.1 g XeF4 and convert it to PF5..
the one that produces the least amount of PF5 is the one you count as your answer..
:)


and for the 2nd question you set it up the same way...

158 g Al convert to Fe
and 263.2 g Fe2O3 and convert to Fe..

the one that produces the least amount of product you consider your answer..

you never add the 2 together..
:)
 
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