- C=C : 835
- C≡C : 612
Answer:
The order of increasing bond lenght :
-C≡C < -C=C < -C-C
Explanation:
Bond length is defined as average distance between two nuclei of bonded atoms in a molecule.Bond length is inversely proportional to the number of bonds present between two atoms.
...[1]
Bond energy is defied as amount of energy required to break apart the bond of 1 mole of molecule into their individual atom.
Bond energy is directly proportional to the number of bonds present between two atoms.
..[2]
From [1] and [2]:
Bond : Energy (kJ/mol)
-C-C : 346
-C=C : 612
-C≡C : 835
The order of decreasing bond energy :
835 kJ/mol > 612 kJ/mol > 346 kJ/mol
The order of increasing bond lenght :
-C≡C < -C=C < -C-C
The mass of 4.35 ×10⁶ atoms of carbon-12 atom is 8.668×10 g.
A mole is a standard specific unit prescribed for measuring large quantities of entities which are very small such as atoms, molecules.It represents large number of units that is 6.022×10²³.
It was previously defined as the number which were experimentally determined to be found in 12 grams of carbon-12.Number of atoms in a mole is same for all substances.
Concept of mole provides quantitative information as to what happens in chemical reaction at a macroscopic level.It is used for determination of simplest formula of a compound.
For all practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons.
Learn more about moles here:
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B. exothermic.
C. spontaneous.
D. endothermic.
The order of increasing atomic radius for the elements Li, Na, K, and Rb is Li
The arrangement of the following elements in increasing atomic radius: Li, Na, K, and Rb indicates that the atomic radius increases as we move down a group in the periodic table. This group of elements, Li, Na, K, and Rb, are all alkali metals and exhibit similar chemical behaviors. As the atomic number or Z increases, the atomic radius also increases. For example, Lithium (Li) has an atomic number of 3, Sodium (Na) 11, Potassium (K) 19, and Rubidium (Rb) 37. As we move down the group from Li to Rb, both Z and the atomic radius increase.
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(1) Br2 (3) CH4
(2) CO2 (4) NH3
represents a polar molecule.
Further Explanation:
The attraction between atoms, molecules or ions responsible for the formation of chemical compounds is a chemical bond. It is formed either due to electrostatic forces or by the sharing of electrons.
The bond that results from the complete transference of electrons between metals and non-metals is an ionic bond. Metals, being electropositive in nature, have the tendency to lose electrons whereas non-metals tend to gain electrons due to their high electronegativity. Cations are formed by metal atoms while non-metals form anions with the gain of electrons.
The bond formed by mutual sharing of electrons between bonded atoms is a covalent bond. Such bonds usually exist between two or more non-metals.
The polarity of a bond depends on the electronegativity difference between the bonded atoms. The more electronegative atom will attract electrons more towards itself, thereby developing negative charge on itself and leaving the less electronegative atom with positive charge. Symmetry also plays an important role to determine whether a molecule will be polar or not. If symmetry is present in a molecule it will be non-polar, even there is an electronegativity difference between the bonded atoms.
(1)
This is formed by the combination of two Br atoms so there is no electronegativity difference between the bonded atoms and therefore this molecule is non-polar in nature (For structure, refer to the attached image).
(2)
This molecule is composed of one carbon and two oxygen atoms but is symmetrical in nature so dipole moment gets cancelled out and therefore is non-polar in nature (For structure, refer to the attached image).
(3)
This molecule consists of one carbon and four hydrogen atoms but is symmetrical in nature so dipole moment gets cancelled out and therefore is non-polar in nature (For structure, refer to the attached image).
(4)
This molecule is composed of one nitrogen and three hydrogen atoms. But N is more electronegative than H so this is polar molecular due to electronegativity difference. Also, this is unsymmetrical molecule (For structure, refer to the attached image) and therefore it is polar in nature.
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Answer details:
Grade: High School
Subject: Chemistry
Chapter: Ionic and covalent compounds
Keywords: polar, non-polar, CH4, CO2, Br2, NH3, symmetrical, dipole moment, chemical bond, ionic bond, covalent bond.
4)NH3
NH3 is an asymmetrical molecule with a pyramidal shape.