Answer: The chemical equation for the formation one mole of 
from its elements in their standard states is 
Explanation:
The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states.
The chemical equation for the formation one mole of from its elements in their standard states is:
where (s) represents solid state and (g) represents gaseous state.
Answer:
false
Explanation:
Because in a periodic table they are not located below each other and therefore do not have the same number of electrons.
A polar bond is formed with atoms having different electronegativities. The bonding electrons are attracted more towards the atom with greater electronegativity resulting in unequal sharing of electrons. Therefore the molecule develop partial charges and becomes polar. Polar molecules have dipole moment that is the partial charge on molecules due to differences in electronegativity between atoms.
A non-polar bond is formed with atoms having the same electronegativity, hence the bonded pair of electron is shared equally between atoms. Non-polar molecules have no moment.
Note that: symmetrical molecules having polar bonds are non-polar because the dipoles of the bond exert equal and opposite effect. Hence the dipoles cancel the charges.
Example: HCl
In HCl, Cl is more electronegative therefore Cl atom pulls the electron pair of the covalent bond towards itself and develops a partial negative charge. Consequently H develops a partial positive charge. This therfore leads to the formation of a dipole.
Air Pressure drops more rapidly with altitude in a column of cold air than in warm air.The answers to this question are cold air and warm air, respectively.
<span>Cold air is known to be dense while warm air is known otherwise to be less thens which makes it move upwards. Cold air experiences more pressure as it moves upwards.</span>
