Answer is: 7,826 kg of cryolite.
Chemical reaction: Al₂O₃ + 6NaOH + 12HF → 2Na₃AlF₆ + 9H₂<span>O.
m(</span>Al₂O₃) = 12,1 kg = 12100 g.
n(Al₂O₃) = m(Al₂O₃) ÷ M(Al₂O₃).
n(Al₂O₃) = 12100 g ÷ 101,96 g/mol = 111,86 mol; limiting reactant.
m(NaOH) = 60,4 kg = 60400 g.
n(NaOH) = 60400 g ÷ 40 g/mol.
n(NaOH) = 1510 mol.
m(HF) = 60,4 kg = 60400 g.
n(HF) = 60400 g ÷ 20 g/mol = 3020 mol.
From chemical reaction: n(Al₂O₃) : n(Na₃AlF₆) = 6 : 2.
n(Na₃AlF₆) = 2 ·111,86 mol ÷ 6 = 37,28 mol.
m(Na₃AlF₆) = 37,28 mol · 209,94 g/mol.
m(Na₃AlF₆) = 7826,56 g = 7,826 kg.
Answer:
C. 101.5°C
Explanation:
The computation of the boiling point of a solution is shown below:
As we know that
where,
i = Factor of Van’t Hoff i.e 2KBr
K_b = Boiling point i.e 0.512° C
m = molality 
Now place the values to the above formula
So, the boiling point is
After solving this, the t is
= 100° C + 1.536° C
= 101.536° C
Hence, the correct option is C.
Answer:
a
Explanation:
a mixture is a material made up of two or more different substances which are not chemically combined. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.
Answer:
It becomes insoluble again.
Explanation:
The chemical equation showing the reaction between benzoic acid, and sodium hydroxide,NaOH is given below;
C6H5COOH + NaOH ------------------------> C6H5COO^- Na^+ + H2O.
The Benzoic acid, C6H5COOH is insoluble but when it reacted with 1M Sodium hydroxide, NaOH it changes to sodium benzoate, C6H5COO^- Na^+ which is more soluble than the benzoic acid.
C6H5COO^- Na^+ + HCl -------------------> C6H5COOH + NaCl.
When the sodium benzoate, C6H5COO^- Na^+ reacts with 6M HCl, it is converted back to benzoic acid which is insoluble. Hence, precipitation is observed.
Explanation: Oxygen plays a very vital role in the life of aquatic animals. The dissolved oxygen in the water helps them to breathe under water.
Optimum level of oxygen for deep living animals like oysters, bottom feeders, crabs is around (1-6 mg/L), while the animals living on the upper side like fishes require a higher amount of around (4-6 mg/L).
If the oxygen concentration in the pond is not optimum, there will no aquatic life and hence, the ecosystem will be affected.
Hence, oxygen concentration affects the fishes that live in the pond to a higher extent.
