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3 years ago

14. The noble gases in Group 18 are very reactive. * O True O False

Chemistry

1 answer:

Soloha48 [4]3 years ago

5 0

Answer: the answer is True

Explanation:

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List the bonding pairs H and I; S and O; K and Br; Si and Cl, H and F; Se and S; C and H in order of increasing covalent charact

stellarik [79]

Answer:

1. (S,O) < (Se,S) < (C,H) = (H,I) = (H,F) < (Si,Cl) < (K,Br)

Explanation:

The covalent character always increases down the group, this is because ionic character decreases down the group and also electronegativity.

In the same way, Covalent character always decreases across a period because electronegativity increases across a period.

The higher the electronegativity values between the two atoms, the more ionic it will be.

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____________ tautomers have a C=O and an additional C-H bond.

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Ch = sh = why and find the stuff

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3 years ago

WILL GIVE 50 POINTS FOR ALL ANSWERS!!! PLEASE HELP!

blondinia [14]

Answer:

the answer would be (A.) and (D.).

Explanation:

the reason for that being is because if calcium sulfate is a main component of plaster of paris you would need to find out what is in it that makes it the main component aka (the formula) therefore part of the answer is (A.). The other part of the answer was (D.) because you would need to find the amount of calcium sulfate that contain 12 grams of oxegeon atoms because you finding the answer to that could lead to the answer of what is the main component of plaster of Paris.

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3 years ago

What is the charge of an electron A. -1 B. 0 C. +1 D. +2

Gelneren [198K]

Answer:

Explanation:

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3 years ago

Write packing efficiency of fcc ,BCC, SCC and formula also . ?

Minchanka [31]

❖ Packing Efficiency ❖

➪ The percentage of total space occupied by particles is called packing efficiency.

$\\ \qquad{\rule{200pt}{3pt}}$

$\bigstar \boxed{ \sf \: \bigg(Packing \; effeciency = \dfrac{Total \; value \; of \; sphere}{Volume \; of \; unit \; cell} \times 100 \bigg)}$

❖ Packing efficiency of simple cubic structure (SCC).❖

$\rm \: {Let \: } \bf{r } \: \rm{ be \: the \: radius \: of \: a \: sphere }\: \\ \rm and \: \bf{a} \: \rm {be \: the \: edge \: of \: unit \: cell.} \\ \\ \; \bigstar \boxed{ \sf{Volume_{(sphere)} = \dfrac{4}{3} \pi r^3}} \bigstar$

❒ Since, simple cubic unit cell contain 1 atom (sphere). So, the total volume of sphere will be :

$: : \implies \sf \: 1 \times \dfrac{4}{3}\pi r^3 = \dfrac{4}{3}\pi r^3$

Volume of unit cell = a³

Volume of unit cell = (2r)³

Volume of unit cell = 8r³

❒ Now, we know that,❒

$\bigstar \boxed{ \sf \: \bigg(Packing \; effeciency = \dfrac{Total \; value \; of \; sphere}{Volume \; of \; unit \; cell} \times 100 \bigg)}$

➪ Substituting the known values in the formula, we get the following results:

$: : \implies \rm \: {\dfrac{\dfrac{4}{3}\pi r^3}{8r^3} \times 100} \\ \\ : : \implies \dfrac{\pi}{6} \times 100 \\\\\ : : \implies \bf {52.4 \%}$

❒ Hence, the packing efficiency of simple cubic structure is 52.4%.

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➪ Packing efficiency of cubic close packing (SCC)/face centred cubic structure (FCC).

❒ Since, simple cubic unit cell contain 2 atom (sphere). So, the total volume of sphere will be:

$: : \implies \rm 4 \times \dfrac{4}{3}\pi r^3 = \dfrac{16}{3}\pi r^3$

Volume of unit cell = a³

Volume of unit cell = (2√2r)³

Volume of unit cell = 16√2r³

❒ Now, we know that,❒

$\bigstar \boxed{ \sf \: \bigg(Packing \; effeciency = \dfrac{Total \; value \; of \; sphere}{Volume \; of \; unit \; cell} \times 100 \bigg)}$

➪Substituting the known values in the formula, we get the following results:

$: : \implies \rm {\dfrac{\dfrac{16}{3}\pi r^3}{16\sqrt{2}r^3} \times 100 }\\\\ \implies \rm \dfrac{\pi}{3\sqrt{2}} \times 100 \\\\\ \implies\bf52.4 \%$

❖ Hence, the packing efficiency of face centred cubic structure is 74%.

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❖ Packing efficiency of body cubic structure (BCC).

❒ Since, simple cubic unit cell contain 2 atom (sphere). So, the total volume of sphere will be:

$: : \implies \rm \: 2 \times \dfrac{4}{3}\pi r^3 = \dfrac{8}{3}\pi r^3$

Volume of unit cell = a³

Volume of unit cell = (4r/√3)³

Volume of unit cell = 64r³/3√3

❒ Now, we know that,❒

$\bigstar \boxed{ \sf \: \bigg(Packing \; effeciency = \dfrac{Total \; value \; of \; sphere}{Volume \; of \; unit \; cell} \times 100 \bigg)}$

➪Substituting the known values in the formula, we get the following results:

$: : \implies \rm {\dfrac{\dfrac{8}{3}\pi r^3}{\dfrac{64r^3}{3\sqrt{3}}} \times 100} \\\\ \implies \dfrac{3\pi}{8} \times 100 \\\ \\ \bf \implies \: 68 \%$

❒ Hence, the packing efficiency of body centred cubic structure is 68%.

$\\ \qquad{\rule{200pt}{3pt}}$

6 0

2 years ago