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Licemer1 [7]
2 years ago
5

Write the merits and demerits of Mendeleev periodic table in points and explain each of them in short​

Chemistry
1 answer:
elena-14-01-66 [18.8K]2 years ago
6 0

Answer:

merits of mendeleev periodic table are:

  1. it was first scientific and systamatic study of different element.
  2. there were may gaps for in discovered elements.After their discovery the got their proper place in table.
  3. with the help of mendeleev periodic table , properties of several elements were studied correctly.

demerits of mendeleev periodic table

  1. it could not arrange hydrogen as it shows the property of both alkali and halogens.
  2. it could not arrange isotopes because they have different atomic weight but same atomic number.
  3. it could not arrange Lanthanides and Actinides.

hope these points helped you

need more points then comment it .

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Which of the following statements is accurate
Rufina [12.5K]
A. If an objects velocity is decreasing, the object is said to be decelerating not accelerating.
B. If an objects velocity changes, it is either experiencing acceleration or deceleration 
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D. If an objects velocity remains constant, its acceleration is zero. 

∴ B is correct
3 0
3 years ago
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51. The radius of gold is 144 pm and the density is 19.32 g/cm3. Does elemental gold have a face-centered cubic structure or a b
Serjik [45]

Answer:

Elemental gold to have a Face-centered cubic structure.

Explanation:

From the information given:

Radius of gold = 144 pm

Its density = 19.32 g/cm³

Assuming the structure is a face-centered cubic structure, we can determine the density of the crystal by using the following:

a = \sqrt{8} r

a = \sqrt{8} \times 144 pm

a = 407 pm

In a unit cell, Volume (V) = a³

V = (407 pm)³

V = 6.74 × 10⁷ pm³

V = 6.74 × 10⁻²³ cm³

Recall that:

Net no. of an atom in an FCC unit cell = 4

Thus;

density = \dfrac{mass}{volume}

density = \dfrac{ 4 \ atm ( 196.97 \ g/mol) (\dfrac{1 \ mol }{6.022 \times 10^{23} \ atoms})}{6.74 \times 10^{-23} \ cm^3}

density d = 19.41 g/cm³

Similarly; For a  body-centered cubic structure

r = \dfrac{\sqrt{3}}{4}a

where;

r = 144

144 = \dfrac{\sqrt{3}}{4}a

a = \dfrac{144 \times 4}{\sqrt{3}}

a = 332.56 pm

In a unit cell, Volume V = a³

V = (332.56 pm)³

V = 3.68 × 10⁷ pm³

V  3.68 × 10⁻²³   cm³

Recall that:

Net no. of atoms in BCC cell = 2

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density = \dfrac{mass}{volume}

density = \dfrac{ 2 \ atm ( 196.97 \ g/mol) (\dfrac{1 \ mol }{6.022 \times 10^{23} \ atoms})}{3.68 \times 10^{-23} \ cm^3}

density =17.78 g/cm³

From the two calculate densities, we will realize that the density in the face-centered cubic structure is closer to the given density.

This makes the elemental gold to have a Face-centered cubic structure.

3 0
3 years ago
Suppose you have a spherical balloon filled with air at room temperature and 1.0 atm pressure; its radius is 17 cm. You take the
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<span>Answer: 17.8 cm
</span>

<span>Explanation:
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<span>1) Since temperature is constant, you use Boyle's law:
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<span>PV = constant => P₁V₁ = P₂V₂


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<span>3) Replacing in the equation V₁/V₂ = P₂/P₁:


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<span>
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4 0
3 years ago
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How many milliliters of a 0.40%(w/v) solution of nalorphine must be injected to obtain a dose of 1.5 mg?
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The number  of Ml  of  a  0.40 %w/v solution  of   ,nalorphine  that must  be injected  to  obtain  a  dose  of 1.5 mg is  calculated as  below


since M/v%   is  mass  of solute  in  grams per 100  ml

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volume is therefore =  100 (  mass/ M/v%)

= 100  x(  0.0015/ 0.4) =  0.375  ML
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3 years ago
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