All categories

3 years ago

In a certain crystalline material the vacancy concentration at 25 c is one-fourth that at 80

Chemistry

1 answer:

Luba_88 [7]3 years ago

3 0

At 93 °C, the vacancy concentration will be three times that at 80°C.

The formula for the vacancy concentration in a crystal is a form of the Arrhenius equation.

In logarithmic form, the equation is

ln(N_2/N_1) = (-Q/R)(1/T_2-1/T_1)

where

• Q = the energy required for vacancy formation

• N_2 = the vacancy concentration at T_2

• N_1 = the vacancy concentration at T_1

• R = the gas constant [8.314 J·K^(-1)mol^(-1)]

Let N_80 represent the vacancy concentration at 80 °C.

At 25 °C, ln(N_25/N_80) = ln(0.25N_80/N_80) = ln0.25 = -1.386

∴ -1.386 =(-Q/R)(1/298.15 – 1/353.15) = -1.306 × 10^(-4) × (Q/R)

Q/R = (-1.386)/[-1.306 × 10^(-4)] = 10 620

At T_2, ln(N_T2/N_80) = ln[(3N_80)/N_80] = ln3 = 1.099

∴ 1.099 = -10 620(1/T_2 – 1/353.15) = -10 620/T_2 + 10 620/353.15

= -10 620/T_2 + 30.072

10 620/T_2 = 30.072 – 1.099 = 28.97

T_2 = 10 620/28.97 = 366.4 K = 93 °C

You might be interested in

How many grams are in 6.00 moles of NaCl?

Anastasy [175]

Is it 350.4, I assume?

5 0

3 years ago

Read 2 more answers

(c) O2 gas is transferred from a 3 L vessel containing oxygen at 4 atm to an evacuated 20 L vessel at a constant temperature of

Fudgin [204]

Answer:

After the transfer the pressure inside the 20 L vessel is 0.6 atm.

Explanation:

Considering O2 as an ideal gas, it is at an initial state (1) with V1 = 3L and P1 = 4 atm. And a final state (2) with V2 = 20L. The temperature remain constant at all the process, thus here applies the Boyle-Mariotte law. This law establishes that at a constant temperature an ideal gas the relationship between pressure and volume remain constant at all time:

$P x V = k$

Therefore, for this problem the step by step explanation is:

$P_{1} xV_{1} = P_{2} xV_{2}$

Clearing P2 and replacing

$P_{2}= \frac{P_{1} xV_{1}}{V_{2} } = \frac{4atmx3L}{20L} = 0.6atm$

7 0

3 years ago

Which of the following electron configurations describes an element that is a noble gas?

butalik [34]

Answer:

The answer to your question is: letter D.

Explanation:

Noble gases are located in group VIIIA of the periodic table, this means that they have 8 eight electrons in their outermost shell.

Due to this characteristic, they are stable and do not react with other elements.

a. 1s22s22p4 The outermost shell of this electron configuration has 6 electrons, then this element has 6 electrons not 8. This configuration is of an element of the group VIA.

b. [Ne]2s22p2 The outermost shell of this element has 4 electrons, so this is not the configuration of a noble gas.

c. [Ar] 3s1 This element only has one electron in its outermost shell, so this is the electron configuration of an alkaline metal.

d. 1s22s22p6 This element has 8 electrons in its outermost shell, so this is the electron configuration of a noble gas.

5 0

3 years ago

Read 2 more answers

Nitrogen gas is more abundant in our atmosphere than oxygen! However, nitrogen needs to be converted into different forms to be

Pavlova-9 [17]

Explanation:

(A)role of nittogen fixing bacteria

=Nitrogen-fixing bacteria, microorganisms capable of transforming atmospheric nitrogen into fixed nitrogen (inorganic compounds usable by plants). More than 90 percent of all nitrogen fixation is effected by these organisms, which thus play an important role in the nitrogen cycle.

B)role of nitrifying bacteria

=Nitrifying bacteria convert the most reduced form of soil nitrogen, ammonia, into its most oxidized form, nitrate. In itself, this is important for soil ecosystem function, in controlling losses of soil nitrogen through leaching and denitrification of nitrate.

C)role of denitrifying bacteria

=Denitrifying bacteria converts nitrates back to nitrogen gas.

4 0

3 years ago

Why is a bannana curved?

Yanka [14]

Answer:

Explanation:

It's because of the sun! Bananas are curved so they can retrieve sunlight.

7 0

3 years ago

Read 2 more answers