Physics, Chemistry & Maths Glossary

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W

Walli's Formula

$\int\limits_0^{{\pi\over2}}{\sin^m x\cos ^n xdx={{[(m-1)(m-3)..................2or1][(n-1)(n-3)...............2or1]}\over {[(m+n)(m+n-2).................2or1]}}}$

Multiply the above result by $\frac{\pi}{2}$ only when both n and m are even (treat o as even).

What does G represent in Newland's Law of Octaves?

H 1
Li 2
G 3
Bo 4
C 5
N 6
O 7

F 8
Na 9
Mg 10
Al 11
Si 12
P 13
S 14

Cl 15
K 16
Ca 17
Cr 19
Ti 18
Mn 20
Fe 21

Co & Ni 22
Cu 23
Zn 25
Y 24
In 26
As 27
Se 28

Br 29
Rb 30
Sr 31
Ce & La 33
Zr 32
Di & Mo 34
Ro & Ru 35

Pd 36
Ag 37
Cd 38
U 40
Sn 39
Sb 41
Te 43

I 42
Cs 44
Ba & V 45
Ta 46
W 47
Nb 48
Au 49

Pt & Ir 50
Os 51
Hg 52
Tl 53
Pb 54
Bi 55
Th 56

Ans: Berilium. The full form of G is glucinum

What is the role of asbestos in Wire Gauze?

In short the answer is even distribution of heat. Bit more.... asbestos has ill health effects due to which ceramic is used these days. Both of these evenly distribute heat from the burner to the sample.

wire-gauze.PNG

Why is Chloroform stored in closed dark coloured bottles?

Chloroform is slowly oxidised by Oxygen present in air in the presence of light to Carbonyl Chloride (Phosgene) - an extremely poisonous gas - by the following reaction,

$2CHC{l_3} + {O_2}\xrightarrow{{light}}\mathop {2COC{l_2}}\limits_{Phosgene} + 2HCl$

By storing it in closed dark coloured bottles, this is prevented.