You are given 68 g of aluminum (Al) and excess water. How many grams of aluminum oxide (Al2O3) can you make? 4 Al + 3O2 --> 2Al2O3

Question 13 options:

95.84 g Al2O3

2.52 g Al2O3

128.48 g Al2O3

101.96 g Al2O3

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

it is the most commonly accepted one

it is b that is the answer.