<h3><u>Answer;</u></h3>
Dipole-dipole and hydrogen bonding
<h3><u>Explanation;</u></h3>
- <em><u>A solution of water and ethanol contains the dipole-dipole forces and hydrogen bonds as the intermolecular forces between molecules.</u></em>
- <em><u>Hydrogen bonding is a type of interactions between molecules that occurs when a partially negative atom such as oxygen end of one of the molecules is attracted to a partially positive hydrogen end of another molecule.</u></em>
- <em><u>Dipole-dipole forces</u></em> results from the unsymmetrical distribution of electrons, thus the polarity does not balance, thus resulting to a dipole attraction between molecules.
Answer:
pH =3.8
Explanation:
Lets call the monoprotic weak acid HA, the dissociation equilibria in water will be:
HA + H₂O ⇄ H₃O⁺ + A⁻ with Ka = [ H₃O⁺] x [A⁻]/ [HA]
The pH is the negative log of the H₃O⁺ concentration, we know the equilibrium constant, Ka and the original acid concentration. So we will need to find the [H₃O⁺] to solve this question.
In order to do that lets set up the ICE table helper which accounts for the species at equilibrium:
HA H₃O⁺ A⁻
Initial, M 0.40 0 0
Change , M -x +x +x
Equilibrium, M 0.40 - x x x
Lets express these concentrations in terms of the equilibrium constant:
Ka = x² / (0.40 - x )
Now the equilibrium constant is so small ( very little dissociation of HA ) that is safe to approximate 0.40 - x to 0.40,
7.3 x 10⁻⁶ = x² / 0.40 ⇒ x = √( 7.3 x 10⁻⁶ x 0.40 ) = 1.71 x 10⁻³
[H₃O⁺] = 1.71 x 10⁻³
Indeed 1.71 x 10⁻³ is small compared to 0.40 (0.4 %). To be a good approximation our value should be less or equal to 5 %.
pH = - log ( 1.71 x 10⁻³ ) = 3.8
Note: when the aprroximation is greater than 5 % we will need to solve the resulting quadratic equation.
As the number of electrons added to the same principal energy level increases, atomic size generally
C. Decreases.
Answer:
1249.88 mol.
Explanation:
∵ no. of moles of Fe = mass of Fe/atomic weight of Fe.
<em>∴ no. of moles of Fe </em>= (6.98 x 10⁴ g)/(55.845 g/mol) = <em>1249.88 mol.</em>
When it has sunlight and water
