Answer:
(A) pH < 1 the predominant form is the cation: H3C-C(H)(NH3+)-COOH
(B) pH = pl the predominant form is the zwitterion H3C-C(H)(NH3+)-COO-
(C) pH > 11 the predominant form is the anion: H3C-C(H)(NH2)-COO-
(D) Does not occurs in any significant pH: H3C-C(H)(NH2)-COOH
Explanation:
Amino acids are bifunctional because they have an amine group and a carboxyl group. The amine group is a weak base and the carboxyl group is a weak acid, but the pKa of both groups will depend on the whole structure of the amino acid. Also, every amino acid has an isoelectric point (pI), which means the pH were the predominant form of the amino acid is the zwitterion. The structure of the alanine (CH3CH2NH2COOH) shows it has the carboxyl group at C1 with a pKa1 of 2.3 and the amino group at C2 whit the pKa2 of 9.7. The isoelectric poin (pI) of Alanine is 6. Consequently, the protonation of the molecule will depend on the pH of the solution. There are three possibilities:
1) If the pH is under the pKa of the carboxyl group (2.3) the predominant form will be with the amino group protonated, forming a cation (CH3CH(NH3+)COOH).
2) If the pH is between pKa1 (2.3) and pKa2 (9.7) the predominant form will be the zwitterion (CH3CH(NH3+)(COO-)).
3) If the pH is upper the pKa2 of the amino group (9.7) the predominant form will be with the carboxyl group deprotonated, forming an anion (CH3CHNH2(COO-)).
The Options are as follow,
<span> (1) CaCl</span>₂<span> (s) (3) CH</span>₃<span>OH (l)</span>
<span> (2) C</span>₂<span>H</span>₆<span> (g) (4) Cal</span>₂<span> (aq)</span>
Answer:
Option-1 is the correct answer.
Explanation:
As we know crystal formation is the property of solids. Therefore, in given options we are given with four different states of matter.
Option A, CaCl₂ is in a solid state , so it can exist in crystal form.
Option 2, C₂H₆ (Ethane) is in gas form, so it cannot form crystals.
Option 3, CH₃OH (Methanol) is present in liquid form, so it fails to form crystals.
Option 4, CaI₂, it is dissolved in water, Hence, it is in aqueous state, Therefore it also lacks crystal structure.
<span>There
are a number of ways to express concentration of a solution. This includes
molarity. Molarity is expressed as the number of moles of solute per volume of
the solution. We calculate the mass of the solute by first determining the number of moles needed. And by using the molar mass, we can convert it to units of mass.
Moles </span>(nh4)3po4 = 0.250 L (0.150 M) = 0.0375 moles (nh4)3po4
Mass = 0.0375 mol (nh4)3po4 (149.0867 g / mol) = 5.59 g (nh4)3po4
Answer:
1.123x10⁻⁴ moles of alanine
Explanation:
In order to convert grams of alanine into moles, <em>we need to know its molecular weight</em>:
The formula for alanine is C₃H₇NO₂, meaning <u>its molecular weight would be</u>:
- 12*3 + 7*1 + 14 + 16*2 = 89 g/mol
Then we <u>divide the sample mass by the molecular weight</u>, to do the conversion:
- 1.0x10⁻² g ÷ 89 g/mol = 1.123x10⁻⁴ moles
