Answers:
Hydrogen bond is formed when positive end of one molecule attracted negative end of other molecule. The concept is similar to magnetic attraction where opposite poles attract each other.
Explanation:
While understanding hydrogen bond, two terms are important, one is electronegativity (tendency of atoms to attract electrons towards itself) and other is dipole (separation of positive and negative charge in a molecule). Hydrogen bond is always formed between hydrogen atom and other atoms having electronegativity different than hydrogen.
Differ from Ionic and Covalent Bonds:
Hydrogen bond is weaker than ionic and covalent bond. Ionic and covalent bonds are intramolecular (within the molecule) whereas hydrogen bond is intermolecular (between molecules).
Example:
Formation of hydrogen bonding in water.
7 is atomic symbol 9 is atomic density 8 is the atomic number
Answer:
10 mol/kg.
Explanation:
Molality can be defined as the number of moles of solute divided by the mass of solvent.
Number of moles = mass/molar mass
= 25/25
= 1 mol.
Mass of solvent in kg = 100 g * 1 kg/1000 g
= 0.1 kg
Molality, m = 1/0.1
= 10 mol/kg.
We are told we have a 14% w/v solution, where w/v is weight/volume. We are asked to prepare 1 L of a 1:4000 solution which can also be written as (1/4000) x 100% = 0.025% w/v solution.
The formula needed here is C1V1 = C2V2 where C1 is the initial concentration, V1 is the initial volume, C2 is the new concentration, and V2 is the new volume.
C1 = 14%
C2 = 0.025 %
V2 = 1 L = 1000 mL
V1 = ?
We must solve for the initial volume V1, which will tell us how much of the initial solution to use.
(14)(V1) = (0.025)(1000 mL)
V1 = 25/14
V1 = 1.8 mL
We will require 1.8 mL of the initial 14% w/v topical antiseptic solution to prepare 1L of a 0.025% w/v solution.