The heat required to vaporize 43.9 g of acetone at its boiling point is calculated as below
the heat of vaporization of acetone at its boiling point is 29.1 kj/mole
find the moles of acetone = mass/molar mass
= 43.9g /58 g/mol =0.757 moles
heat (Q) = moles x heat of vaporization
= 29.1 kj/mole x 0.757 moles = 22.03 kj
Answer:
HF
H₂S
H₂CO₃
NH₄⁺
Explanation:
<em>Which acid in each of the following pairs has the stronger conjugate base?</em>
According to Bronsted-Lowry acid-base theory, <em>the weaker an acid, the stronger its conjugate acid</em>. Especially for weak acids, pKa gives information about the strength of such acid. <em>The higher the pKa, the weaker the acid.</em>
<em />
- Of the acids HCl or HF, the one with the stronger conjugate base is HF because it is a weak acid.
- Of the acids H₂S or HNO₂, the one with the stronger conjugate base is H₂S because it is a weaker acid. pKa (H₂S) = 7.04 > pKa (HNO₂) = 3.39
- Of the acids H₂CO₃ or HClO₄, the one with the stronger conjugate base is H₂CO₃ because it is a weak acid.
- Of the acids HF or NH₄⁺, the one with the stronger conjugate base is NH₄⁺ because it is a weaker acid. pKa (HF) = 3.17 < pKa (NH₄⁺) = 9.25
Answer:
a. Phosphoric Acid
b. Acetic Acid
c. Hypochlorous Acid
Explanation:
A buffer works when the pH of this one is in pKa ± 1. That means, to find which buffer system works in some pH you need to find pKa:
pKa = -log Ka
<em>pKa Acetic acid:</em>
-log1.8x10⁻⁵ = 4.74
<em>pKa phosphoric acid:</em>
-log7.5x10⁻³ = 2.12
<em>pKa hypochlorous acid:</em>
-log3.5x10⁻⁸ = 7.46
a. For a pH of 2.8 the best choice is phophoric acid because its effective range is: 1.12 - 3.12 and 2.8 is between these values.
b. pH 4.5. Acetic acid. effective between pH's 3.74 - 5.74
c. pH 7.5. Hypochlorous acid that works between 6.46 and 8.46
The balanced net reactiion for the following half cells will be
Sn + Cr²⁺ ---> Sn²⁺ + Cr
<h3>What are
Half cells ?</h3>
A half cell is one of the two electrodes of an electrochemical cell.
An electrochemical cell comprises two half cells, where every half cell contains an electrode and an electrolyte.
A salt bridge or direct contact is needed to connect two half cells.
The balanced net reactiion for the given half cells will be
Sn + Cr²⁺ ---> Sn²⁺ + Cr
Learn more about Half cell here ;
brainly.com/question/1313684
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