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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: jlamping on September 17, 2004, 03:35:07 PM

Title: ??
Post by: jlamping on September 17, 2004, 03:35:07 PM
A sample of 26.4g of aluminum yields 260.8g of aluminum bromide.  How many grams of bromide react with 16.4g of aluminum?
Title: Re:??
Post by: Donaldson Tan on September 18, 2004, 03:45:45 PM
A sample of 26.4g of aluminum yields 260.8g of aluminum bromide.  

It's obvious that the 260.8g of aluminium bromide formed contains 26.4g of Aluminum by composition (with reference to Law Of Mass Combination). By deducing the number of moles of Aluminium and Bromine from their respective mass combination, you can deduce the emperical formula of Aluminium Bromide.

How many grams of bromide react with 16.4g of aluminum?

Once you have derrived the emperial formula of aluminium bromide, you can deduce how many moles of bromine has reacted with the number of moles of aluminium equivalent to 16.4g
Title: Re:??
Post by: Demotivator on September 18, 2004, 04:08:49 PM
It's simpler to just set up a proportions equation:
grams Al (1)/grams Br(1) = grams Al(2)/grams Br(2)
where grams Br(1) = (260.8 -  26.4) g
solve for  grams Br(2)