Question

how many atoms in total are there in 1.83 mol of aluminum oxide molecules?
a. 2.20×10²⁴
b. 1.10×10²⁴
c. 6.61×10²⁴
d. 5.51×10²⁴
a
b
c
d
in the balanced chemical equation 2h₂+o₂→2h₂o, if 4.0 moles of h₂ react completely, how many moles of h₂o will be produced?
1.0 mole
2.0 moles
8.0 moles
4.0 moles

Explanation:

First Question (Atoms in Aluminum Oxide)

Step1: Determine Formula of Aluminum Oxide

Aluminum oxide is $\ce{Al2O3}$, so each molecule has $2 + 3 = 5$ atoms.

Step2: Calculate Molecules Using Avogadro's Number

Moles of $\ce{Al2O3}$ = $1.83$ mol. Molecules = $n \times N_A = 1.83\ \text{mol} \times 6.022 \times 10^{23}\ \text{molecules/mol}$.

Step3: Calculate Total Atoms

Total atoms = Molecules $\times$ Atoms per Molecule = $1.83 \times 6.022 \times 10^{23} \times 5$.
$1.83 \times 6.022 \approx 10.99$, $10.99 \times 5 \approx 54.95$, $54.95 \times 10^{23} \approx 5.51 \times 10^{24}$.

Step1: Analyze Balanced Equation

The equation is $\ce{2H2 + O2 -> 2H2O}$. The mole ratio of $\ce{H2}$ to $\ce{H2O}$ is $2:2 = 1:1$.

Step2: Apply Mole Ratio

Moles of $\ce{H2}$ = $4.0$ mol. Since ratio is $1:1$, moles of $\ce{H2O}$ = moles of $\ce{H2}$ = $4.0$ mol.

Answer:

d. $5.51 \times 10^{24}$

Second Question (Moles of $\ce{H2O}$ Produced)