Question

1) How many aluminum atoms are there in 3.50 grams of Al2O3?
(a) 2.45 x 1022
(b) 2.07 x 1022
(c) 1.68 x 1022
(d) 4.90 x 1022
(e) 4.13 x 1022

Answer 1

Answer:

Aluminium atoms =  4.13 *10^22 aluminium atoms

The correct answer is E

Explanation:

Step 1: Data given

Mass of Al2O3 = 3.50 grams

Molar mass of Al2O3 = 101.96 g/mol

Number of Avogadro = 6.022 * 10^23 /mol

Step 2: Calculate moles Al2O3

Moles Al2O3 = mass Al2O3 / molar mass Al2O3

Moles Al2O3 = 3.50 grams / 101.96 g/mol

Moles Al2O3 = 0.0343 moles

Step 3: Calculate moles Aluminium

In 1 mol Al2O3 we have 2 moles Al

in 0.0343 moles Al2O3 we have 2*0.0343 = 0.0686 moles Al

Step 4: Calculate aluminium atoms

Aluminium atoms =  moles aluminium * Number of Avogadro

Aluminium atoms =  0.0686 * 6.022 * 10^23

Aluminium atoms =  4.13 *10^22 aluminium atoms

The correct answer is E

Answer 2

The number of atoms of aluminum in 3.5 grams of the given compound is $4.13 \times 10^{22} \ atoms$.

The given parameters;

• mass of the aluminum oxide, $Al_2O_3$ = 3.5 g

The molecular mass of the given aluminum oxide is calculated as follows;

$Al_2O_3$ = (27 x 2) + (16 x 3) = 102 g/mol

The number of moles of the given mass of the aluminum oxide is calculated as follows;

$no. \ moles = \frac{Reacting \ mass}{Molar \ mass} \\\\no. \ moles = \frac{3.5}{102} = 0.0343 \ mole$

In 1 mole of $Al_2O_3$  -------------- 2 (6.02 x 10²³ atoms of Al)

0.0343 mole of $Al_2O_3$  ---------- ?

$= 0.0343 \times 2 \times 6.022 \times 10^{23} \\\\= 4.13 \times 10^{22} \ atoms$

Thus, the number of atoms of aluminum in 3.5 grams of the given compound is $4.13 \times 10^{22} \ atoms$

Learn more here:https://brainly.com/question/11461637