Consider the balanced chemical equation when 18.3 g Al is reacted with 113 g Iā‚‚ to form AlIā‚ƒ(g).
What is the mass in grams of the excess Al remaining after the partial reaction of 18.3 g Al with 113 g Iā‚‚?
2 Al(s) + 3 Iā‚‚(g) → 2 AlIā‚ƒ(g)

Respuesta :

Answer:

10.3 g Al

Explanation:

To find the excess mass of Al, you need to (1) convert grams Iā‚‚ to moles Iā‚‚ Ā (via molar mass), then (2) convert moles Iā‚‚ to moles AlIā‚ƒ (via mole-to-mole ratio from equation coefficients), then (3) convert moles AlIā‚ƒ to grams AlIā‚ƒ (via molar mass). Now that you have the actual amount of AlIā‚ƒ produced, you need to (4) convert grams AlIā‚ƒ to moles AlIā‚ƒ (via molar mass), then (5) convert moles AlIā‚ƒ to moles Al (via mole-to-mole ratio from equation coefficients), and then (6) convert moles Al to grams Al (via molar mass). Now that you know the amount of Al actually needed to produce the product, you need to (7) find the excess mass of Al.

Molar Mass (Al): 26.982 g/mol

Molar Mass (Iā‚‚): 2(126.90 g/mol)

Molar Mass (Iā‚‚): 253.8 g/mol

Molar Mass (AlIā‚ƒ): 26.982 g/mol + 3(126.90 g/mol)

Molar Mass (AlIā‚ƒ): 407.682 g/mol

2 Al(s) + 3 Iā‚‚(g) -------> 2 AlIā‚ƒ(g)

Ā 113 g Iā‚‚ Ā  Ā  Ā  Ā  Ā  1 mole Ā  Ā  Ā  Ā  Ā  Ā  2 moles AlIā‚ƒ Ā  Ā  Ā  Ā  Ā 407.682 g
------------- Ā x Ā ---------------- Ā x Ā ---------------------- Ā x Ā ------------------- Ā = Ā 121 g AlIā‚ƒ
Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā 253.8 g Ā  Ā  Ā  Ā  Ā  Ā  3 moles Iā‚‚ Ā  Ā  Ā  Ā  Ā  Ā  Ā  1 mole

121 g AlIā‚ƒ Ā  Ā  Ā  Ā  Ā  1 mole Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā 2 moles Al Ā  Ā  Ā  Ā  Ā  26.982 g
--------------- Ā x Ā ------------------ Ā x Ā --------------------- Ā x Ā ----------------- Ā = Ā 8.01 g Al
Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  Ā  407.682 g Ā  Ā  Ā  Ā  Ā 2 moles AlIā‚ƒ Ā  Ā  Ā  Ā  Ā  1 mole

Starting Amount - Mass Needed = Excess

18.3 g Al - 8.01 g Al = 10.3 g Al