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3 years ago

The most useful ore of aluminum is bauxite, in which Al is present as hydrated oxides, Al2O3 * xH2O.

Chemistry

1 answer:

lesantik [10]3 years ago

6 0

Answer:

44.7 kWh

Explanation:

Let's consider the reduction of Al₂O₃ to Al in the Bayer process.

6 e⁻ + 3 H₂O + Al₂O₃ → 2 Al + 6 OH⁻

We can establish the following relations:

The molar mass of Al is 26.98 g/mol.
2 moles of Al are produced when 6 moles of e⁻ circulate.
1 mol of e⁻ has a charge of 96468 c (Faraday's constant).
1 V = 1 J/c
1 kWh = 3.6 × 10⁶ J

When the applied electromotive force is 5.00 V, the energy required to produce 3.00 kg (3.00 × 10³ g) of aluminum is:

$3.00 \times 10^{3} gAl.\frac{1molAl}{26.98gAl} .\frac{6mole^{-}}{2molAl}.\frac{96468c}{1mole^{-}}.\frac{5.00J}{c}.\frac{1kWh}{3.6 \times 10^{6}J} =44.7kWh$

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. Sulfur dioxide can be produced in the laboratory by the reaction of hydrochloric acid and a sulfite salt such as sodium sulfit

shutvik [7]

Answer:

Mass of SO₂ can be made from 25.0 g of Na₂SO₃ and 22 g of HCl = 12.672 g

Explanation:

SO₂( sulfur dioxide) can be produced in the lab. by the reaction of hydrochloric acid & sulphite salt such as sodium.

the balanced chemical equation is as follows

Na₂SO₃ + 2 HCl → 2 NaCl + SO₂ + H₂O

Moles of Na₂SO₃ = $\frac{Mass}{Molecular mass} =\frac{25}{126} = 0.198$

Moles of HCl = $\frac{mass}{molecular mass}=\frac{22}{36.5}= 0.6$

using mole ratio method to find limiting reagent

For sodium sulfite $\frac{mole}{stoichiometry} = \frac{0.198}{1}= 0.198$

for HCl $\frac{mole}{stoichiometry} = \frac{0.6}{2}= 0.3$

since sodium sulfite is limiting reactant for above chemical reaction

1 mole of Na₂SO₃ produce 1 mole of SO₂

0.198 mole of Na₂SO₃ produce 0.198 mole of SO₂

∴ Mass of SO₂ produce = mole x molar mass of SO₂

= 0.198 x 64

= 12.672 g

8 0

3 years ago

A 40.0-mL sample of 0.100 M HNO2 (Ka = 4.6 x 10-4 .) is titrated with 0.200 M KOH. Calculate: a. the pH when no base is added b.

In-s [12.5K]

Answer:

a) 2.173

b) 20ml

c) 3.87

d) 4.35

e) 8.8

f) 12.45

Explanation:

chech the attachment for explanationns

4 0

3 years ago

The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction. This can be gleane

GenaCL600 [577]

Answer : The total mass of oxygen gas released in the reaction will be, 12.8 grams

Explanation :

Law of conservation of mass : It states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.

This also means that total mass on the reactant side must be equal to the total mass on the product side.

The balanced chemical reaction will be,

$2MgO\rightarrow 2Mg+O_2$