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2 years ago

What was johann dobereiner contribution to the periodic table

Chemistry

1 answer:

k0ka [10]2 years ago

3 0

Answer:

he introduced triads of similar chemical properties in periodic table.

Explanation:

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The volume density of atoms for a bcc lattice is 5 x 1026 m-3. Assume that the atoms are hard spheres with each atom touching it

ollegr [7]

Explanation:

It is known that for a body centered cubic unit cell there are 2 atoms per unit cell.

This means that volume occupied by 2 atoms is equal to volume of the unit cell.

So, according to the volume density

$5 \times 10^{26} atoms = 1 [tex]m^{3}$

2 atoms = $\frac{1 m^{3}}{5 \times 10^{26} atoms} \times 2 atoms$

= $4 \times 10^{-27} m^{3}$

Formula for volume of a cube is $a^{3}$ . Therefore,

Volume of the cube = $4 \times 10^{-27} m^{3}$

As lattice constant (a) = $(4 \times 10^{-27} m^{3})^{\frac{1}{3}}$

= $1.59 \times 10^{-9} m$

Therefore, the value of lattice constant is $1.59 \times 10^{-9} m$ .

And, for bcc unit cell the value of radius is as follows.

r = $\frac{\sqrt{3}}{4}a$

Hence, effective radius of the atom is calculated as follows.

r = $\frac{\sqrt{3}}{4}a$

= $\frac{\sqrt{3}}{4} \times 1.59 \times 10^{-9} m$

= $6.9 \times 10^{-10} m$

Hence, the value of effective radius of the atom is $6.9 \times 10^{-10} m$ .

3 0

3 years ago

A certain weak acid, ha, has a ka value of 6.0×10−7. calculate the percent ionization of ha in a 0.10 m solution.

joja [24]

For the purpose, we will use the equation for determining the dissociation constant from concentration and <span>percent of ionization:

Kd = c </span>× α²

α = √(Kd/c) × 100%

Kd = 6.0×10⁻⁷

c(HA) = 0.1M

α = √(6.0×10⁻⁷/0.1) × 100% = 0.23%

So, in the solution, the acid <span>percent of ionization will be just 0.23%.</span>

5 0

3 years ago

4. All of the following are examples of natural causes of air pollution

erma4kov [3.2K]

Answer:

factory emissions

Explanation:

8 0

3 years ago

Which organism is the carnivore in this food web?

mihalych1998 [28]

Among the choices, the only one that can be considered a carnivore is C. Adelie penguin. Adelie penguins are found in the Arctic, and feed on aquatic creatures such as krill, fish, and squid. Krill is a type of crustacean that feeds on phytoplankton, which is at the bottom of the food chain.

8 0

3 years ago

At what elevation would there be the highest atmospheric pressure?

Reika [66]

Answer:

The highest sea-level pressure on Earth occurs in Siberia

Explanation:

where the Siberian High often attains a sea-level pressure above 1050 mbar (105 kPa; 31 inHg), with record highs close to 1085 mbar (108.5 kPa; 32.0 inHg).

4 0

3 years ago