Answer:
64.6% of Br and 35.4% of Sr
Step-by-step explanation:
The percentage composition is obtained defining the percentage in mass of each atom in a molecule.
To solve this question we must find the mass of each atom in 1 mole:
Molar mass Br: 79.904g/mol
Molar mass Sr: 87.62g/mol
The molar mass of SrBr2 is:
79.904g/mol*2 + 87.62g/mol =
159.808g/mol + 87.62g/mol =
247.428g/mol
The percentage of Br is:
79.904g/mol*2 = 159.808g/mol / 247.428g/mol * 100
= 64.6% of Br
And percentage of Sr is:
87.62g/mol / 247.428g/mol * 100
= 35.4% of Sr