Answer:
pH = 9.03
Explanation:
The equilibrium of the NH₄Cl / NH₃ buffer in water is:
NH₃ + H₂O ⇄ NH₄⁺ + OH⁻
Initial moles of both NH₃ and NH₄⁺ are:
0.100L ₓ (0.20 mol / L) = <em>0.0200 moles </em>
The NH₃ reacts with HCl producing NH₄⁺, thus:
NH₃ + HCl → NH₄⁺ + Cl⁻
<em>That means, moles of HCl added to the solution are the same moles are consumed of NH₃ and produced of NH₄⁺</em>
Moles added of HCl were:
0.025L ₓ (0.20mol / L) = 0.0050 moles of HCl. Thus, final moles of NH₃ and NH₄⁺ are:
NH₃: 0.0200 moles - 0.0050 moles = 0.0150 moles
NH₄⁺: 0.0200 moles + 0.0050 moles = 0.0250 moles.
Using H-H equation for bases:
pOH = pKb + log [NH₄⁺] / [NH₃]
<em>Where pKb is -log Kb =</em><em> 4.745</em><em>.</em>
Replacing:
pOH = 4.745 + log 0.0250mol / 0.0150mol
pOH = 4.967
As pH = 14- pOH
<em>pH = 9.03</em>
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You should have given us a table, but I think my table shouldn't be too different.
Let's put oxidation numbers first.
You would have to know that Mg(s) is a reducing agent and Br2(l) is an oxidizing agent. But it is pretty common knowledge that the halogens will tend to take the electrons and alkali and alkaline earth metals will tend to give up electrons.
Mg is oxidized because it gives up electrons; Br2(l) is reduced because it gains electrons. Since the reaction conforms to what we would expect to <em>naturally</em> (thermodynamically favored) occur, it can take place given that the activation energy is supplied.
<span>Earthquakes, tsunamis, the rise of hills and mountains, change the course of rivers
</span>
1. 45.0 L H2S ( 1 mol / 22.4 L) ( 3 mol O2 / 2 mol H2S ) ( 22.4 L / 1 mol ) = 67.5 L O2 needed
2.<span>s- sphere, holds 2; p- dun bell, holds 6; d- complex, holds 10; f- very complex, holds 14
3.</span>In an ionic bond, oppositely charged ions are held together by the electronic force of attraction that exists between oppositely charged particles. In the ionic compound, anions and cations are present in a ratio that causes the total charge on the compound to be zero. Sodium phosphide, Na3 P, has three sodium ions for each phosphide ion. This ratio insures a zero total charge given the charges on the two individual ions (Na = 1+, P = 3-).
