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:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.