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Dharam Das Bhoyar 5 years ago
Jasmeen Kaur 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
In the solid state (ice), intermolecular interactions lead to a highly ordered but loose structure in which each oxygen atom is surrounded by 4 hydrogen atoms; two of these hydrogen atoms are covalently bonded to the oxygen atom, and the two others (at longer distances) are hydrogen bonded to the oxygen atom’s unshared electron pairs.
this open structure of ice causes its density to be less than that of the liquid state, in which the ordered structure is partially broken down and the water molecules are (on average) closer together. When water freezes, a variety of structures are possible depending on the conditions. 9 different forms of ice are known and can be interchanged by varying external pressure and temperature.
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Yogita Ingle 5 years, 1 month ago
When a protic acid (HX) is added to an asymmetric alkene, the acidic hydrogen attaches itself to the carbon having a greater number of hydrogen substituents whereas the halide group attaches itself to the carbon atom which has a greater number of alkyl substituents.
It is important to note that the Markovnikov’s rule was developed specifically for its application in the addition reaction of hydrogen halides to alkenes.
Posted by Durgesh Nandini 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
In chemistry, the most commonly used unit for molarity is the number of moles per litre, having the unit symbol mol/L or mol⋅dm−3 in SI unit. A solution with a concentration of 1 mol/L is said to be 1 molar, commonly designated as 1 M.
Yogita Ingle 5 years, 1 month ago
Molarity is the number of moles of a substance per liter of solution, also known as molar concentration. A capital M signifies solutions labeled with molar concentration.
SI units molarity : mol dm-3.
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Sonami Barik 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
The representation of molecules in Lewis electron dot structure or just a Lewis structure is in honor of the American chemist Gilbert Newton Lewis.
Lewis dot structures also called electron dot structures are diagrams that describe the chemical bonding between atoms in a molecule. They also display the total number of lone pairs present in each of the atoms that constitute the molecule. Lewis dot structures are commonly referred to as electron dot structures or Lewis structures. Lewis defined a base as an electron pair donor and an acid as an electron pair acceptor.
Posted by Sonami Barik 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
|
MOLAR MASS |
MOLECULAR MASS |
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Refers to mass of a mole of a substance |
Refers to the mass of molecules |
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Also known as molecular weight |
It determines the mass of single molecule |
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SI unit is g/mol to use in higher calculations |
Measured in amu |
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It is defined as the mass of Avogadro number of atoms/molecules or compounds |
No particular melting point |
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Measurement given to compounds, atoms or molecules |
Determined only in molecules |
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Less accurate than molecular mass |
Accurate to use in higher calculations |
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Example: Mass of 1 mole of oxygen is 15.9994 grams. Therefore the molar mass = 15.9994 g/mol |
Example: Molecular mass of Ca(OH)2 = 74 atomic mass units |
Posted by Sourav Raj 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
They are set of 4 numbers, which give complete information about the address of electron.
There are 4 types of quantum numbers:
- Principal quantum number.
- Azimuthal quantum number.
- Magnetic quantum number.
- Spin quantum number.
Posted by Shivani Sharma 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
A mole is defined as the mass of the substance which consists of the equal quantity of basic units. Example atoms in 12 grams are the same as 12C. The basic units can be molecules, atoms or formula units based on the substance. A mole fraction indicates the number of chemical elements. One mole of any substance is equal to the value of 6.023 x 1023 (Avagadro number). It can be used to measure the products obtained from the chemical reaction. The unit is denoted by mol.
The formula for the number of moles formula is expressed as
Number of Moles = mass of substance/, the mass of one mole
Example 1: Determine the number of moles in 95g of MnO2.
Solution:
Given
Mass of MnO2 = 95g
Mass of one mole MnO2 = 86.94g
Number of moles formula is
Number of moles = Mass of substance / Mass of one mole
Number of moles = 95 / 86.94
Number of moles = 1.092 mol
Posted by Divyanshi Goswami 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
Moles of methanol present in 2.5 L of 0.25 M solution
Moles of CH3OH = 2.5 * 0.25 = 0.625
Mass of CH3OH = 0.625 * 32 = 20 g
(∵ Molecular mass of CH3OH = 12 + 1 * 3 + 16 + 1 = 32)
0.793 * g of CH3OH is present in 1000 mL
20 g of CH3OH is present in
= mL
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Yogita Ingle 5 years, 1 month ago
The term “isotope” mainly refers to the variation in the atomic mass or weight of an element.
It is also defined as variants of a particular element where these variants will have the same number of protons but differ in the number of neutrons in the atom.
When we look at carbon it also has three isotopes namely Carbon-12, Carbon-13, and Carbon-14. The numbers 12, 13, and 14 are the isotopes’ atomic masses. Here, Carbon-12 is a stable isotope whereas carbon-14 is mostly a radioactive isotope.
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Yogita Ingle 5 years, 1 month ago
The causes of formation of a chemical bond are: Tendency of atoms to complete their octets or duplets by rearrangement of their valence electrons (octed theory). The system acquires minimum energy when atoms are at some equilibrium distance where attractive forces dominate over repulsive forces.
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Yogita Ingle 5 years, 1 month ago
The average atomic mass of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance (the decimal associated with percent of atoms of that element that are of a given isotope).
Average atomic mass = f1M1 + f2M2 + … + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope.
Posted by Divyanshi Goswami 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
Gay-Lussac\'s Law of Combining Volumes:
When gases react, they do so in volumes which bear a simple ratio to one another, and to the volume of the gaseous product, provided that all the volumes are measured at the same temperature and pressure.
Example:
One volume of hydrogen when mixed with one volume of chlorine, gives two volumes of hydrogen chloride gas at the same temperature and pressure.
H2 + Cl2 ? 2HCl
Thus the ratio 1:1:2 is simple.
Rupam Vishwakaram 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Molarity is no. if moles of solute per volume of solution (in litre)
therefore moles of NaCl is 5.85/58.5 = 0.1
volume of solution is 0.5 litre
molarity = 0.1/0.5 = 0.2
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