Given the chemical reaction:
[tex]\[ 4 \text{Al} + 3 \text{O}_2 \rightarrow 2 \text{Al}_2\text{O}_3 \][/tex]

In this chemical reaction, how many grams of [tex]\(\text{Al}_2\text{O}_3\)[/tex] will be produced if 375 grams of Al react completely? Express your answer to three significant figures.

There will be [tex]\(\square\)[/tex] grams of [tex]\(\text{Al}_2\text{O}_3\)[/tex].



Answer :

Alright, let's solve this step-by-step.

Step 1: Determine the molar masses

- The molar mass of Aluminum (Al) is 26.98 grams per mole.
- The molar mass of Aluminum Oxide (Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex]) is calculated as follows:

[tex]\[ \text{Molar mass of } Al_2O_3 = 2 \times 26.98 \text{ (for Al)} + 3 \times 16 \text{ (for O)} = 53.96 + 48 = 101.96 \text{ g/mol} \][/tex]

Step 2: Calculate the moles of Aluminum (Al)
- Given mass of Aluminum is 375 grams.
- To find the moles of Al, we use the formula:

[tex]\[ \text{Moles of Al} = \frac{\text{mass of Al}}{\text{molar mass of Al}} = \frac{375 \text{ grams}}{26.98 \text{ g/mol}} \approx 13.899 \text{ moles} \][/tex]

Step 3: Determine the moles of Aluminum Oxide (Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex]) produced

- According to the balanced chemical equation:

[tex]\[ 4 \text{ Al} \rightarrow 2 \text{ Al}_2\text{O}_3 \][/tex]

- This reaction implies that 4 moles of Al produces 2 moles of Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex].
- Therefore, the moles of Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex] produced will be half the moles of Al, as given by the ratio (2/4):

[tex]\[ \text{Moles of Al}_2\text{O}_3 = 13.899 \text{ moles of Al} \times \frac{2}{4} = 6.95 \text{ moles of Al}_2\text{O}_3 \][/tex]

Step 4: Convert the moles of Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex] to grams

- Using the molar mass of Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex] (101.96 g/mol), we find the mass of Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex]:

[tex]\[ \text{Mass of Al}_2\text{O}_3 = \text{moles of Al}_2\text{O}_3 \times \text{molar mass of Al}_2\text{O}_3 = 6.95 \text{ moles} \times 101.96 \text{ g/mol} \approx 708.58 \text{ grams} \][/tex]

Final Result:

The mass of Aluminum Oxide (Al[tex]\(_2\)[/tex]O[tex]\(_3\)[/tex]) produced when 375 grams of Aluminum (Al) react completely is:

[tex]\[ \boxed{708.58} \text{ grams of Al}_2\text{O}_3 \][/tex]