Determine the difference between archaea and bacteria. (1 point)

Calculate the equilibrium number of vacancies per cubic meter for copper at 1000K. The energy for vacancy formation is 0.9eV/ato

nexus9112 [7]

Answer:

Therefore the equilibrium number of vacancies per unit cubic meter =2.34×10²⁴ vacancies/ mole

Explanation:

The equilibrium number of of vacancies is denoted by $N_v$ .

It is depends on

total no. of atomic number(N)
energy required for vacancy
Boltzmann's constant (k)= 8.62×10⁻⁵ev K⁻¹
temperature (T).

$N_v=Ne^{-\frac{Q_v}{kT} }$

To find equilibrium number of of vacancies we have find N.

$N=\frac{N_A\ \rho}{A_{cu}}$

Here ρ= 8.45 g/cm³ =8.45 ×10⁶m³

$N_A$ = Avogadro Number = 6.023×10²³

$A_{Cu}$ = 63.5 g/mole

$N=\frac{6.023\times 10^{23}\times 8.45\times 10^{6}}{63.5}$

$=8.01\times 10^{28$ g/mole

Here $Q_v$ =0.9 ev/atom , T= 1000k

Therefore the equilibrium number of vacancies per unit cubic meter,

$N_v=( 8.01\times 10^{28}) e^{-(\frac{0.9}{8.62\times10^{-5}\times 1000})$

=2.34×10²⁴ vacancies/ mole

3 0

3 years ago

Calcium must lose two electrons to get a full outer shell. what is the name of the group to which calcium belongs

11111nata11111 [884]

The answer to this question would be: alkaline earth metal

Alkali earth metal is the second column group of the periodic table. In this group, the element has 2 extra electrons in their outer cells. That is why most of this metal has 2+ charge.
Their neighbor is the alkali metal which was the first column of the periodic table. The name is similar so don't confused and mix them each other.

4 0

3 years ago

A science club made pine wood cars. Each car was set on the same track and then released. The distance traveled was measured. Li

Minchanka [31]

Isn't this a math problem?
If it is the the answer should be 102.

10 decimeters=1 meter

27x10=270
270-168=102

7 0

3 years ago

Metals posses varying reduction potentials. Iron can reduce Cu+2 (aq) to copper metal. Silver can reduce Au+ (aq) to gold metal.

natta225 [31]

Answer: The true statement is iron can reduce $Au^+(aq)$ to gold metal

Explanation:

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

$A+BC\rightarrow AC+B$

Metal A is more reactive than metal B.

We are given:

Iron can reduce copper, silver can reduce gold, sodium can reduce iron and copper can reduce silver metal.

The increasing order of reactivity thus follows:

$Au$

where, sodium is most reactive and gold is least reactive

For the given options:

Option 1: Copper cannot easily reduce sodium ion to sodium metal because it is less reactive.

$Cu(s)+Na^+(aq.)\rightarrow \text{ No reaction}$

Option 2: Iron cant easily reduce gold ion to gold metal because it is more reactive.

$Fe(s)+3Au^+(aq.)\rightarrow Fe^{3+}(aq.)+3Au(s)$

Option 3: Silver cannot easily reduce iron ion to iron metal because it is less reactive.

$Ag(s)+Fe^{3+}(aq.)\rightarrow \text{ No reaction}$

Hence, the true statement is iron can reduce $Au^+(aq)$ to gold metal

7 0

3 years ago

How is the mass of 1 mole of an element determined? O A. It is equal to the atomic mass times Avogadro's number. O B. It is the

evablogger [386]

Answer:

Avogadro's number is the number of particles in one mole of anything. In this context, it is the number of atoms in one mole of an element. It's easy to find the mass of a single atom using Avogadro's number. Simply divide the relative atomic mass of the element by Avogadro's number to get the answer in grams.

4 0

3 years ago