A piece of aluminum foil 1.00cm square and 0.590mm thick is allowed to react with bromine to form aluminum bromide. Part A How many moles of aluminum were used? (The density of aluminum is 2.699 g/cm^3 Part B How many grams of aluminum bromide form, assuming that the aluminum reacts completely?

Respuesta :

Answer:

Part A: 5.899x10^-3 moles of Al

Part B: 1.573 g of AlBr3

Explanation:

Part A: We have to obtain the volume of the piece of aluminium; all sides of the square must be in cm. Then, use the density to obtain the mass.

[tex]0.590 mm  (\frac{1 cm}{10 mm}) = 0.059 cm[/tex]

[tex]V= lxlxl= (1cm)(1cm)(0.059 cm)= 0.059 cm^3.[/tex]

0.059 is the volume of the Al udes for the reaction. Now, to oabtain the moles:

[tex]0.059 cm^3 Al(\frac{2.699 g Al}{1 cm^3 Al})(\frac{1 mol Al}{27 g Al})= 5.899x10^-3 moles[/tex]

Part B: To obatin the mass of AlBr3, we need the balanced chemical equation:

                                               2Al + 3Br2 → 2AlBr3

We assume bromine (Br2) is in excess, therefore, we calculate the aluminum bromide formed from the Al:

[tex]5.898 x 10^-3 moles Al (\frac{2 moles AlBr3}{2 moles Al}) (\frac{266.7 g AlBr3}{1 mol AlBr3}) = 1.573 g[/tex] of Al

Part A: [tex]5.899*10^{-3}[/tex] moles of Al

Part B: [tex]1.573 g[/tex] of AlBr₃

Part A:

We have to obtain the volume of the piece of aluminum; all sides of the square must be in cm. Then, use the density to obtain the mass.

1mm = 10 cm

[tex]0.590mm*\frac{1cm}{10mm}=0.059cm[/tex]

As we know, Volume is the product of length, breadth and height, It can be written as:

[tex]\text{Volume}=l*b*h\\\\\text{Volume}=1*1*0.059\\\\\text{Volume}=0.59cm^3[/tex]

Calculation for moles:

0.059 is the volume of the Al is used for the reaction. Now, to obtain the moles:

[tex]0.509cm^3Al*\frac{2.699g Al}{1cm^3Al} *\frac{1mol Al}{27g Al}=5.899*10^{-3}moles[/tex]

Part B:

To obtain the mass of AlBr₃, we need the balanced chemical equation:

2Al + 3Br₂ → 2AlBr₃

We assume bromine (Br₂) is in excess, therefore, we calculate the aluminum bromide formed from the Al:

[tex]5.89*10^{-3}\text{ moles of Al }*\frac{\text{ 2 moles of } AgBr_3}{\text{ 2 moles of Al} }*\frac{266.7g AlBr_3}{1 mol AlBr_3} =1.573 \text{ g of Al }[/tex]

Thus,

Part A: [tex]5.899*10^{-3}[/tex] moles of Al

Part B: [tex]1.573 g[/tex] of AlBr₃

Find more information about calculation of  moles here:

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