Chemistry
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New answer posted
11 months agoContributor-Level 10
1.38 We apply pythagoras theorem AC2= AB2+ BC2
(2R)2= (R+r)2 +(R+r)2 = 2(R+r)2
4R2 = 2(R+r)2
(2R)2= (R+r)2
√2(R)2= √(R+r)2 = √2r = R+r
r = √2 R – R
r = (√2-1) R
r = (1.4114-1)R
r= 0.414 R
New answer posted
11 months agoContributor-Level 10
1.37 Calculation of edge length of unit cell(a)
Atomic mass of the element (M)= 93g mol−1
Number of particles in bcc type unit cell (Z) = 2
Mass of the unit cell = Z * MNA = 2 * (93 g mol−1) (6.022*1023mol−1)
=30.89*10−23g
Density of unit cell (d) =8.55 g cm−3
Volume of unit cell (a3)=Mass of unit cell
Density of unit cell=(30.89*10−23g)(8.55 g cm−3)
=36.16*10−24cm3
Edge length of unit cell (a) = (36.13*10−24cm3)13
=3.31 * 10−8cm
Step II: Calculation of radius of unit cell (r)
For bcc structure, r=√3a4
=√3*(3.31*10−8cm)4
=1.43*10−8cm
New answer posted
11 months agoContributor-Level 10
(a) Eutrophication: When the growth of algae increases in the surface of water, dissolved oxygen in water is reduced. This phenomenon is known as eutrophication. (Due to this growth of fish gets inhibited).
(b) Pneumoconiosis: It is a disease which irritates lungs. It causes scarring or fibrosis of the lung.
(c) Photochemical smog: Photochemical smog is formed as a result of the photochemical decomposition of nitrogen dioxide and chemical reactions involving hydrocarbons. It takes place during dry warm season in the presence of sunlight. It is oxidising in nature.
(d) C
New answer posted
11 months agoContributor-Level 10
1.36 It is given that the atoms of Q are present at the corners of the cube.
Therefore, number of atoms of Q in one unit cell = 8 x 1/8 = 1
It is also given that the atoms of P are present at the body-centre.
Therefore, number of atoms of P in one unit cell = 1
This means that the ratio of the number of P atoms to the number of Q atoms, P:Q = 1:1
Hence, the formula of the compound is PQ.
The coordination number of both P and Q is 8.
New answer posted
11 months agoContributor-Level 10
1.35 P= density
A= edge length of the cell
NA= Avogadro Number
Z= no. of atoms in F.C.C unit cell
M= mass of the metal
Edge length of the cell = d = 4.07*10-8 cm
Density = P =10.5g/cm3
No. of unit cell of face centered cubic (F.C.C) lattice is 4, Z=4
Avogadro Number (NA) = 6.022*1023
Mass of silver = M=?
New answer posted
11 months agoContributor-Level 10
A Toxic substance that is used to kill insects is called an insecticide. For example: DDT, BHC.
New answer posted
11 months agoContributor-Level 10
Carbon monoxide (CO), sulphur dioxide (SO2) and oxides of nitrogen (NO2).
New answer posted
11 months agoContributor-Level 10
Green chemistry can be applied as mentioned in the following examples:
(i) In dry-cleaning, the use of liquefied CO2 in place of tetrachloroethene.
(ii) In the bleaching of paper using hydrogen peroxide instead of chlorine.
(iii) In the manufacture of chemicals like ethanol, using environment-friendly chemicals and conditions.
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