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2 years ago

Which of the following giant covalent structures does not have a high melting and boiling

Chemistry

2 answers:

iogann1982 [59]2 years ago

6 0

Answer:

Polythene has the lowest melting/boiling point from all the other covalent structures mentioned in this question.

vaieri [72.5K]2 years ago

5 0

Answer:

Polythene (polyethene according the IUPAC nomenclature.)

Explanation:

Consider the structure of each option:

Polythene: long chains of atoms that are able to rotate along the bonding axis.
Graphite: layers of (hexagonal) carbon sheets; each individual sheet is rigid (allows no rotation.)
Silicon dioxide: three-dimensional (tetrahedral) network of carbon and oxygen atoms; the entire network very rigid (allows no rotation.)
Diamond: three-dimensional (tetrahedral) network of carbon atoms; likewise, the entire tetrahedral network is very rigid.

Melting each structure requires overcoming the forces that hold the structure rigid:

In polythene, van der Waal forces hold the chains together and prevents rotations.
Deshaping graphite requires bending the layers; doing so would require overcoming the covalent bonds within the hexagonal sheets.
In silicon dioxide and diamond, deshaping the tetrahedral network also requires overcoming covalent bonds.

Van der Waal forces are much easier to break than covalent bonds.

Hence, the melting point of polythene would be the lowest among the options.

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jeyben [28]

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3 years ago

Suppose a new group 5A element is discovered. Photoelectron spectroscopy (PES) reveals that its last two peaks occur at 1370 kJ/

iren2701 [21]

Answer: The average valence electron energy (AVEE) of this element =

1014.2 KJ/ mol or 1.0142mJ/mol.

Explanation:

The average valence electron energy = (number of electrons in s subshell x Ionization energy of that subshell) + (number of electrons in p subshell x Ionization energy of that subshell) / total number of electrons in both subshells of the valence shells.

The 5A elements are non-metals like Nitrogen and Phosphorus with the metallic character increasing as you go down the group, So a new 5A element will have characteristics of its group with 5 valence electron in its outermost shell represented as ns2 np3

Therefore the average valence electron energy (AVEE) of this element will be calculated as

The average valence electron energy = (2 x 1370 kJ/mol + 3 x 777 kJ/mol.) / 5

2740+2331/ 5 =5071/5

=1014.2 KJ/ mol or 1.0142mJ/mol.

5 0

3 years ago

In the reaction 2co ( g) + o2( g) → 2co2( g), what is the ratio of moles of oxygen used to moles of co2produced?

KIM [24]

In the reaction 2co ( g) + o2( g) → 2co2( g), the ratio of moles of oxygen used to moles of co2produced is 1:2.

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3 years ago

The empirical formula of glucose is CH2O, and the molecular formula of glucose is 6 times than the empirical formula. What is th

goldfiish [28.3K]

C6H12O6
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3 years ago

Calculate the atomic mass of chromium it’s composition is 83.79% with a mass of 51.94 amu; 9.50% with a mass of 52.94 Amu; 4.35%

Elina [12.6K]

Convert the percentages into decimals (you can do that by dividing the percent by 100), then multiply that by its corresponding mass to find its relative amount/ contribution to the atomic mass of chromium. After doing so, add all of the obtained values together to get the average mass.

 83.79% = .08379
9.50% = .095
4.35% = .0435
2.36% = .0236

Average mass of chromium = 0.8379(51.94) + 0.095( 52.94) + 0.0435(49.95) + 0.0236(53.94)

Answer: 52amu

P.S. never forget units

8 0

2 years ago