How many grams of Br2 are needed to form 67.1 g of AlBr3 ?

2Al(s)+3Br2(l)⟶2AlBr3(s)

Approximately .

Explanation:

Look up the relative atomic mass of and on a modern periodic table:

Calculate the formula mass of and :

.

Calculate the number of moles of formula units in of :

.

Refer to the balanced equation for this reaction. The ratio between the coefficients of and in that equation is three-to-two. That corresponds to the ratio:

.

It is already calculated that approximately of was produced through this reaction. Apply this ratio to approximate the (minimum) number of moles of that is consumed:

.

Calculate the mass of that of :

.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.