Answer to Question #279735 in Chemistry for alaa

Question

consider the following reaction :2Al + Cr2O3 = Al2O3 +2cr. what is the mass of Al2O3 that will be produced upon complete reaction of 1.20* 10^21 atoms of Al

Answer 1

2Al + Cr₂O₃ = Al₂O₃ +2 Сr

1 mole of matter cntains 6.022×10²³ elementary entities.

1.20x10²¹ atoms of Al equals to 1.20x10²¹/ 6.022×10²³ = 0.2x10^-2 moles.

According to the equation, n (Al₂O₃) = 1/2 x n (Al) = 1/2 x 0.2x10^-2 = 0.001 moles.

n = m / M

m = n x M

M (Al₂O₃) = 102 g/mol

m (Al₂O₃) = n x M = 0.001 x 102 = 0.102 g