Question 1

Which of the following statements best describes the difference between an element and a compound?

Accepted Answer

An element is a substance that cannot be broken down into simpler substances by ordinary chemical means, while a compound consists of two or more different elements chemically bonded together.

Question 2

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 3

A neutral atom of oxygen has 8 protons, 8 neutrons, and 8 electrons. What is its atomic mass number?

Accepted Answer

$$16$$

Question 4

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, causing an unequal sharing of electrons and a partial negative charge on oxygen.

Question 5

Which type of chemical bond is formed when electrons are transferred from one atom to another, resulting in oppositely charged ions?

Accepted Answer

Ionic bond

Question 6

A radioactive isotope of carbon, $$^{14}C$$, is used in dating fossils. What property of $$^{14}C$$ makes it useful for this purpose?

Accepted Answer

It decays at a predictable rate, allowing scientists to estimate the age of fossils based on its half-life.

Question 7

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers maintain pH within normal limits by minimizing changes in hydrogen ion concentration.

Question 8

Which of the following is a correct match of macromolecule and its monomer?

Accepted Answer

Nucleic acid – Nucleotide

Question 9

Which process involves the removal of a water molecule to join two monomers together?

Accepted Answer

Dehydration synthesis

Question 10

Which of the following statements about saturated and unsaturated fatty acids is TRUE?

Accepted Answer

Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

Question 11

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Long-term energy storage.

Question 12

Which level of protein structure is stabilized primarily by hydrogen bonds and involves alpha helices and beta sheets?

Accepted Answer

Secondary structure

Question 13

What is the result of protein denaturation?

Accepted Answer

The protein loses its functional shape and becomes inactive.

Question 14

Which of the following is a correct base pairing in DNA?

Accepted Answer

Adenine pairs with Thymine ($$A = T)$$

Question 15

Which structural feature distinguishes RNA from DNA?

Accepted Answer

RNA contains uracil instead of thymine and is single-stranded.

Question 16

Which of the following best describes the structure of a phospholipid in a cell membrane?

Accepted Answer

A polar head and two nonpolar tails

Question 17

Which of the following is a real-world application of high-level radiation?

Accepted Answer

Sterilizing medical equipment by killing bacteria and fungi

Question 18

A solution has a pH of 4. Which of the following statements is correct?

Accepted Answer

The solution is acidic.

Question 19

Which of the following best describes the relationship between monomers and polymers?

Accepted Answer

Polymers are large molecules formed by joining many monomers together.

Question 20

Which of the following is TRUE about the flow of energy in an ecosystem?

Accepted Answer

Energy flows from sunlight to producers to consumers and is eventually lost as heat.

General Chemistry Foundations: Atoms, Molecules, and Biological Macromolecules

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