PL - Equilibria (acid–base) *01 *02

Question 1

carboxylic acids - functional group

Answer 1

contain the carboxyl group (-COOH)

Question 2

dicarboxylic acid - functional groups

Answer 2

contain two carboxyl groups at either end of the molecule

Question 3

carboxylic acids - strong or weak acids

Answer 3

weak acids

they partially dissociate into carboxylate ions (R-COO-) and H+

Question 4

carboxylic acids - reaction with metals

Answer 4

react with more reactive metals in a redox reaction to form a salt and hydrogen gas

Question 5

carboxylic acids - reaction with carbonates (CO3^2-)

Answer 5

reacts with carbonates to form a salt, carbon dioxide and water

Question 6

carboxylic acids - reactions with aqueous alkalis

Answer 6

react with aqueous alkalis to form salts and water

Question 7

PAG 7

Question 8

what can amino acids exist as ?

Answer 8

zwitterions

Question 9

what is a zwitterion?

Answer 9

an overall neutral molecule that has both a +ve and -ve charged in different parts of the molecule

can only exist as a zwitterion near its isoelectric point - the pH where the overall charge on the amino acid is zero, this depends on the R-group.

Question 10

structure of zwitterions - in conditions more acidic than isoelectric point

Answer 10

H3N+ - CH(R) - COOH

Question 11

structure of zwitterions - in conditions more basic than isoelectric point

Answer 11

H2N - CH(R) - COO-

Question 12

structure of zwitterions - at isoelectric point

Answer 12

H3N+ - CH(R) - COO-

Question 13

amino acids - amino (amine) group nature

Answer 13

basic because the lone pair on the nitrogen (NH2), can accept a H+ ion to give N+H3

Question 14

how do amino acids react

Answer 14

the amino group of one amino acid reacts with the carboxyl group of another

forms a peptide link

condenstation reaction to make