C). 39g of al(oh)3
i have science hw about moles what does this mean

0.5 moles

Explanation:

moles are a way to compare different elements and are used a measurement of the amount of an element or molecule

I think your teacher wants you to convert 39g of Al(OH)3 to moles

we can use a method called stoichiometry to do this.

39g Al(OH)3 x 1 mol Al(OH)3 / 78g Al(OH)3 = 0.5 moles Al(OH)3

I got 78 by adding up the molar masses for Al, 3Os and 3Hs, make sure to add for 3 Os and Hs because of the subscript 3