Answer
The molar mass for $Al_2(SO_4)_3$ is equal to 342.2 g
Work Step by Step
1. Identify the molar mass for each element in this compound:
$Al: 26.98$ g
$S: 32.06$ g
$O: 16.00$ g
2. Multiply each one of them by their respective subscript number, for the elements that are enclosed in brackets, also multiply them by the subscript of the brackets:
$Al: 27.0$ g * 2 = 54.0 g
$S: 32.06$ g * 3 = 96.18 g
$O: 16.00$ g * 4 * 3 = 192.0 g
3. Calculate the total sum of these values:
$54.0g + 96.18g + 192.0g = 342.2g$