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natka813 [3]
2 years ago
8

How many grams of Boron can be obtained from 234 grams of B2O3?

Chemistry
1 answer:
Xelga [282]2 years ago
4 0

Answer:

72.67g of B

Explanation:

The reaction of B₂O₃ to produce boron (B), is:

B₂O₃ → 3/2O₂ + 2B

<em>That means B₂O₃ produce 2 moles of boron</em>

Molar mass of B₂O₃ is 69.62g/mol. 234g of B₂O₃ contains:

234g B₂O₃ ₓ (1mol / 69.62g) = 3.361 moles of B₂O₃.

As 1 mole of B₂O₃ produce 2 moles of B, Moles of B that can be produced from B₂O₃ is:

3.361mol B₂O₃ ₓ 2 = <em>6.722 moles of B</em>.

As molar mass of B is 10.811g/mol. Thus mass of B that can be produced is:

6.722mol B ₓ (10.811g / mol) = <em>72.67g of B</em>

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A vessel contains Ar(g) at a high pressure. Which of the following statements best helps to explain why the measured pressure is
Luda [366]

Answer:

4. The combined volume of the Ar atoms is too large to be negligible compared with the total volume of the container.

Explanation:

Deviations from ideality are due to intermolecular forces and to the nonzero volume of the molecules themselves. At infinite volume, the volume of the molecules themselves is negligible compared with the infinite volume the gas occupies.

However, the volume occupied by the gas molecules must be taken into account. Each <u>molecule does occupy a finite, although small, intrinsic volume.</u>

The non-zero volume of the molecules implies that instead of moving in a given volume V they are limited to doing so in a smaller volume. Thus, the molecules will be closer to each other and repulsive forces will dominate, resulting in greater pressure than the one calculated with the ideal gas law, that means, without considering the volume occupied by the molecules.

5 0
2 years ago
A 20.0-mL sample of lake water was acidified with nitric acid and treated with excess KSCN to form a red complex (KSCN itself is
Novosadov [1.4K]

Answer:

8.09x10⁻⁵M of Fe³⁺

Explanation:

Using Lambert-Beer law, the absorbance of a sample is proportional to its concentration.

In the problem, the Fe³⁺ is reacting with KSCN to produce Fe(SCN)₃ -The red complex-

The concentration of Fe³⁺ in the reference sample is:

4.80x10⁻⁴M Fe³⁺ × (5.0mL / 50.0mL) = 4.80x10⁻⁵M Fe³⁺

<em>Because reference sample was diluted from 5.0mL to 50.0mL.</em>

<em>That means a solution of  4.80x10⁻⁵M Fe³⁺ gives an absorbance of 0.512</em>

Now, as the sample of the lake gives an absorbance of 0.345, its concentration is:

0.345 × (4.80x10⁻⁵M Fe³⁺ / 0.512) = <em>3.23x10⁻⁵M.  </em>

As the solution was diluted from 20.0mL to 50.0mL, the concentration of Fe³⁺ in Jordan lake is:

3.23x10⁻⁵M Fe³⁺ × (50.0mL / 20.0mL) = <em>8.09x10⁻⁵M of Fe³⁺</em>

4 0
2 years ago
A 0.15 m solution of chloroacetic acid has a ph of 1.86. What is the value of ka for this acid?
dem82 [27]

Answer: 1.67\times 10^{-3}

Explanation:

ClCH_2COOH\rightarrow ClCH_2COO^-+H^+

   cM              0             0

c-c\alpha        c\alpha          c\alpha  

So dissociation constant will be:

K_a=\frac{(c\alpha)^{2}}{c-c\alpha}

Given:  c = 0.15 M

pH = 1.86

K_a = ?

Putting in the values we get:

Also pH=-log[H^+]

1.86=-log[H^+]

[H^+]=0.01

[H^+]=c\times \alpha

0.01=0.15\times \alpha

\alpha=0.06

As [H^+]=[ClCH_2COO^-]=0.01

K_a=\frac{(0.01)^2}{(0.15-0.15\times 0.06)}

K_a=1.67\times 10^{-3]

Thus the vale of K_a for the acid is 1.67\times 10^{-3}

4 0
2 years ago
Explain dynamic equilibrium with respect to solution formation. what is a saturated solution? an unsaturated solution? a supersa
gavmur [86]

Initially when we dissolve a solute , rate of dissolution is far exceeding the rate of deposition. But as the concentration of solution increases , the rate of deposition also increases and a situation comes when rate of dissolution becomes equal to rate of deposition that situation is called dynamic equilibrium.

Saturated solution:

It is the solution in which dissolved solute is in dynamic equilibrium with undissolved solute, if we dissolve more solute into it it will not dissolve.

Unsaturated solution:

This solution contains less amount of solute than the equilibrium amount of it. If we dissolve more solute into it , it will dissolve.

Supersaturated solution:

This solution contains more amount of solute than its equilibrium concentration. These solution are unstable.

4 0
2 years ago
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77julia77 [94]

Answer:

OH⁻

Explanation:

A base is defined as a substance which interacts with water to yield excess hydroxide ions, OH⁻, in an aqeous solution.

Examples are Sodium hydroxide (NaOH)

Potassium hydroxide (KOH)

Bases are generally certain metallic oxides, metallic hydroxides and aqueous ammonia.

An acid is a proton donor, H⁺ and it interacts with water to produce excess hydroxonium ions in an aqueous solution.

3 0
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