Question

question 4 3 pts calculate the number of aluminum atoms in 3.42 g of al₂(so₄)₃. the molar mass of al₂(so₄)₃ is 342.14 g/mol. 1.81 x 10²² atoms 1.20 x 10²² atoms 6.02 x 10²⁵ atoms 3.01 x 10²¹ atoms 6.02 x 10²¹ atoms

Explanation:

Step1: Calculate moles of Al₂(SO₄)₃

Use the formula $n=\frac{m}{M}$, where $m = 3.42\ g$ and $M=342.14\ g/mol$. So $n=\frac{3.42}{342.14}\ mol$.

Step2: Determine moles of Al

In 1 mole of Al₂(SO₄)₃, there are 2 moles of Al. So moles of Al, $n_{Al}=2\times\frac{3.42}{342.14}\ mol$.

Step3: Calculate number of Al atoms

Use Avogadro's number $N_A = 6.02\times 10^{23}\ atoms/mol$. Number of Al atoms $N=n_{Al}\times N_A=2\times\frac{3.42}{342.14}\times6.02\times 10^{23}$.
$N = 1.20\times 10^{22}\ atoms$

Answer:

1.20 x 10²² atoms