Question

A chemist needs 1.36 mol of strontium bromide, SrBr2, for a reaction. What mass of strontium chloride should the chemist use?

Answer 1

Mass SrBr2 = 247.42 g/mol x 1.36 mol 
= 336 g

Answer 2

Answer: 336.5 grams

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

convert given masses into moles.

Number of Moles =$\frac{\text{ given mass}}{\text{ molar mass}}$

Given number of moles = 1.36

Molar mass of $SrBr_2$ = 247.43 g/mol

Putting in the values we get

$1.36=\frac{\text {given mass}}{247.43g/mole}$

${\text {given mass}}=336.5grams$

Thus mass of strontium bromide used should be 336.5 grams.