Answer:
Explanation:
All chemical changes requires a substantial amount of energy. Depending on the type of reaction, the energy of reactants and products differs.
In an exothermic chemical change where heat is always given off to the surroundings, the energy of the product is less than that of reactants.
For endothermic changes, the surrounding becomes colder at the end of the reaction. This implies that the heat energy of the product is higher than that of the reactants.
Endothermic reactions are reactions that proceed by the absorption of heat (energy) while exothermic reactions involve a release of energy.
a) Formation of frost on a car window in winter is an exothermic process as heat is liberated when liquid water freezes to form crystals
b) Formation of water condensate on a glass of ice water is an endothermic reaction since heat is absorbed by the cold water from the glass container thereby cooling it.
c) A decrease in the temperature as ammonium nitrate is added to water is an endothermic reaction
Answer:
Option e.
Explanation:
The option 'e' fact about Hydrogen bonds are correct, that is; ''form weak interactions but can provide structural stability when many are found in a single molecule''.
So, what is this Hydrogen bond?
Hydrogen bonds is a kind of strong dipole- dipole attractions. Hydrogen bonding occurs as a result of the bonding between hydrogen and strongly electronegative atoms for example oxygen, Fluorine and so on.
Since we now know what Hydrogen bond is, let us take a look at the options.
(a) for the first option, we can see from above meaning of Hydrogen bonds that Hydrogen bonds occur between Hydrogen and a strong Electronegative atom. So, this option is wrong.
(b). Option 'b' is also wrong Because Hydrogen bonds does not occur between hydrogen and oxygen atoms ONLY but also with other strong Electronegative atoms such as oxygen.
(c). Option 'c' is wrong because between a strong and not only between a weak electronegative atom and hydrogen.
(d). Option 'd' is also not correct.
(e). Option 'e' is correct. Hydrogen bonds contribute to the effect of boiling and melting point of substance, solubilty, dimerization, strength of bonds, shape of molecules and so on
Answer:
Effective nuclear charge and ionization energy decreased down in the column.
Explanation:
Along Group:
As we move from top to bottom in group the atomic size increases with increase of atomic number. The electron is added into the next shell hence the valance electrons farther away from the nucleus and hold of nucleus become weaker on the valance electrons. The addition of electrons also increase the shielding and protect the outer electrons from the hold of nucleus. Thus it becomes easier to remove the electron from an atom and less energy is required that's why ionization energy decreases from top to bottom and effective nuclear charge also decrease because of shielding effect.
Along period:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons and shielding remain constant due to addition of electron in same shell. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases.
Answer: The amount of water formed is 12 moles
Explanation: Please see the attachments below
