Multiple Choice. For each statement, circle the correct answer.

Aluminum has a face-centered cubic unit cell. How many atoms of Al are present in each unit cell

Serjik [45]

Answer:4

Explanation:

As shown in the image attached, a face-centred cubic structure has 8 atoms at the corners and 6 face center atoms.

Each corner atom contributes to eight cell, so per unit cell 1/8 ×8 =1atom

Face center atoms contributes to two unit cells 1/2 × 6=3atoms

Total atoms =3+1=4atoms

Therefore the atoms in Al FCC per unit cell is 4

7 0

3 years ago

The labels have fallen off three bottles containing powdered samples of metals; one contains zinc, one lead, and the other plati

Alinara [238K]

Here we have to identify the metal powder by the given disposal.

The identification of Zinc can be done by 1 m nitric acid (HNO₃) and Ni(NO₃)₂ which will produce hydrogen gas by reaction and displacement reaction as shown below.

Zn + 2 HNO₃ = Zn(NO₃)₂ + H₂ (g)

Zn + Ni(NO₃)₂ = Zn(NO₃)₂ + Ni

The identification of lead can be done by the reaction with 1 m nitric acid (HNO₃) which produces lead nitrate.

The reaction is-

Pb + 4HNO₃ = Pb(NO₃)₂ + 2NO₂ + 2H₂O

The identification of platinum can be done by the reaction with all the given disposal as it will not react with any of the compound.

1. Identification of Zinc (Zn):

(a) Zn metal will not react with sodium nitrate (NaNO₃) as sodium remains at the lower position of the activity series than zinc.

Zn + NaNO₃ = No reaction

(b) Zn metal will react with 1 m HNO₃ to form hydrogen gas. The reaction is:

Zn + 2 HNO₃ = Zn(NO₃)₂ + H₂ (g)

(c) Zn will react with nickel nitrate [Ni(NO₃)₂] because it may only cause displacement reaction the reduction potential of Zn²⁺/Zn (-0.76) is less than that of Ni²⁺/Ni (-0.23). Thus the reaction will be:

Zn + Ni(NO₃)₂ = Zn(NO₃)₂ + Ni

2. Identification of lead (Pb):

(a) Pb metal will not react with sodium nitrate (NaNO₃) as sodium remains at the lower position of the activity series than Pb.

Pb + NaNO₃ = No reaction

(b) Pb reacts with HNO₃ to form lead nitrate. The reaction is:

Pb + 4HNO₃ = Pb(NO₃)₂ + 2NO₂ + 2H₂O

(c) The standard reduction potential of Pb²⁺/Pb is more than nickel Ni²⁺/Ni thus there will be no reaction between Pb and NI(NO₃)₂.

Pb + Ni(NO₃)₂ = No reaction.

3. Identification of platinum (Pt)

(a) Pt metal will not react with sodium nitrate (NaNO₃) as sodium remains at the lower position of the activity series than Pt.

Pt + NaNO₃ = No reaction.

(b) The standard reduction potential of Pt²⁺/Pt is so high (+1.188) thus there will be no reaction with HNO₃.

Pt + HNO₃ = No reaction

(c) The standard reduction potential of Pt²⁺/Pt is more than nickel Ni²⁺/Ni thus there will be no reaction between Pt and Ni(NO₃)₂.

Pt + Ni(NO₃)₂ = No reaction.

8 0

3 years ago

What energy is required to remove the remaining electron from singly ionized helium?

skelet666 [1.2K]

To remove one electron from singly ionized helium, will require approximately 54.4 eV or 8.72 1020 J of energy.

The amount of energy required by an isolated, gaseous molecule in the electronic state of the ground to absorb in order to discharge an electron and produce a cation has been known as the ionization energy. The amount of energy required for every atom in a mole to drop one electron is most often given as kJ/mol.

Anything that causes electrically neutral atoms and molecules to gain or lose electrons in order to become electrically charged atoms as well as molecules .

Therefore, the "To remove one electron from singly ionized helium, will require approximately 54.4 eV or 8.72 1020 J of energy."

To know more about electron

brainly.com/question/14135172

#SPJ4

3 0

1 year ago

I can't find the density of this question I need help

zaharov [31]

Density is Mass divided by volume.

4 0

4 years ago

Which atom, selenium (Se) or Arsenic (As), has the higher electron affinity and why?

IrinaVladis [17]

Answer:

5. Selenium, because it does not have a stable, half-filled p subshell and adding an electron does not decrease its stability.

Explanation:

Electron affinity is the amount of energy released when an isolated gaseous atom accepts electron to form the corresponding anion.

Selenium:-

The electronic configuration of the element is:-

$[Ar]3d^{10}4s^24p^4$

Arsenic:-

The electronic configuration of the element is:-

$[Ar]3d^{10}4s^24p^3$

The 4p orbital in case of arsenic is half filled which makes the element having more stability as compared to selenium.

Thus, selenium has higher electron affinity because adding electron does not decrease the stability as in case of arsenic.

8 0

3 years ago