you would expect an amino acid to contain which two functional groups

HESI A2

Chemistry HESI A2 Practice Test

1. Which two functional groups would you expect an amino acid to contain?

A. R-NH2 and R-COOH
B. R-CHO and R-CO-NH
C. R-OH and R-COOR
D. R-O-R and R-COOH

Correct answer: A

Rationale: Amino acids are organic compounds that are characterized by the presence of an amino group (NH2) and a carboxylic acid group (COOH) in their chemical structure. These two functional groups, found in option A, are fundamental components of amino acids and play crucial roles in their classification and biological functions. Option B contains an aldehyde group (CHO) and an amide group (CO-NH), which are not characteristic functional groups of amino acids. Option C includes a hydroxyl group (OH) and an ester group (COOR), which are not typically present in amino acids. Option D presents ether (R-O-R) and carboxylic acid (COOH) functional groups, which do not represent the functional groups commonly found in amino acids.

2. What is another name for aqueous HI?

A. hydroiodic acid
B. hydrogen monoiodide
C. hydrogen iodide
D. hydriodic acid

Correct answer: D

Rationale: The correct name for aqueous HI is 'hydriodic acid.' When hydrogen iodide (HI) dissolves in water, it forms hydriodic acid. Therefore, 'hydriodic acid' is the appropriate term for aqueous HI. Choice A, 'hydroiodic acid,' is incorrect as it does not reflect the nature of the compound in the aqueous state. Choice B, 'hydrogen monoiodide,' is not a widely recognized term for this compound. Choice C, 'hydrogen iodide,' is the name for HI in the gaseous state, not when it's dissolved in water.

3. What number represents the number of protons an element has?

A. Atomic mass
B. Mass number
C. Atomic number
D. Neutron number

Correct answer: C

Rationale: The correct answer is C, atomic number. The atomic number corresponds to the number of protons in an element. This number is unique to each element and determines its placement on the periodic table. It is equal to the number of protons found in the nucleus of an atom of that element. Choice A, atomic mass, represents the average mass of an element's isotopes. Choice B, mass number, is the sum of protons and neutrons in an atom. Choice D, neutron number, specifically refers to the count of neutrons in an atom and not protons.

4. How many electrons are in a neutral atom of neon?

A. 9
B. 10
C. 11
D. 12

Correct answer: B

Rationale: The atomic number of neon is 10, which represents the number of protons in its nucleus. In a neutral atom, the number of electrons is equal to the number of protons to maintain electrical neutrality. Therefore, a neutral atom of neon contains 10 electrons, matching the 10 protons within the nucleus. Choice A (9 electrons) is incorrect as it doesn't correspond to the atomic number of neon. Choices C (11 electrons) and D (12 electrons) are also incorrect as they do not align with the correct atomic number of neon.

5. What charge do Group IA elements have?

A. +1
B. +2
C. +3
D. 0

Correct answer: A

Rationale: Group IA elements, also known as alkali metals, have a +1 charge. They readily lose one electron to achieve a stable electron configuration, forming ions with a single positive charge. This makes +1 the correct choice. Choices B, C, and D are incorrect because alkali metals in Group IA typically lose one electron, so they do not have a +2, +3, or 0 charge.