What is the approximate charge difference between glutamic acid and acetic acid at pH 9.5?

To determine the approximate charge difference between glutamic acid and acetic acid at pH 9.5, we need to consider their functional groups and the pKa values.

Glutamic acid (Glu) has two ionizable functional groups: the carboxyl group (COOH) with a pKa of approximately 2.2 and the amino group (NH2) with a pKa of approximately 9.7.

Acetic acid (AcOH) has one ionizable functional group: the carboxyl group (COOH) with a pKa of approximately 4.8.

At pH 9.5, both glutamic acid and acetic acid will be deprotonated.

For glutamic acid, the amino group (NH2) will be protonated, but the carboxyl group (COOH) will still be deprotonated. This means that glutamic acid will have a negative charge of -1.

For acetic acid, the carboxyl group (COOH) will be partially deprotonated, which means it will have a small negative charge.

Therefore, the approximate charge difference between glutamic acid and acetic acid at pH 9.5 is that glutamic acid will have a charge of -1, while acetic acid will have a small negative charge.

To determine the approximate charge difference between glutamic acid and acetic acid at pH 9.5, we need to consider their ionization behavior and the pKa values of their functional groups.

Both glutamic acid and acetic acid contain a carboxyl group. At higher pH values, the carboxyl group will deprotonate and become negatively charged. However, glutamic acid contains an additional amino group which can also be protonated or deprotonated depending on the pH.

To calculate the charge difference, we can compare the pKa values of the carboxyl group in glutamic acid (pKa1 ≈ 2.2) and acetic acid (pKa ≈ 4.75). Since the pH of 9.5 is higher than both pKa values, both carboxyl groups in both glutamic acid and acetic acid will be deprotonated.

However, in the case of glutamic acid, the amino group (pKa ≈ 9.67) will still be protonated at pH 9.5, leading to an overall charge of -1 for glutamic acid. On the other hand, acetic acid will only have the deprotonated carboxyl group, resulting in an overall charge of -1 as well.

Therefore, the approximate charge difference between glutamic acid and acetic acid at pH 9.5 is zero. Both molecules will have the same negative charge.