Question 1

Which of the following best describes an isotope?

Accepted Answer

An atom with the same number of protons but a different number of neutrons compared to other atoms of the same element.

Question 2

Which subatomic particle is directly involved in chemical reactions between atoms?

Accepted Answer

Electron

Question 3

A radioactive isotope of carbon, $$^{14}C$$, is used in radiometric dating. If the half-life of $$^{14}C is 5730 $$years, what fraction of the original $$^{14}C$$ remains after 11,460 years?

Accepted Answer

$$\frac{1}{4}$$

Question 4

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

Accepted Answer

Oxygen is more electronegative than hydrogen, resulting in an unequal sharing of electrons and partial charges on the molecule.

Question 5

Which type of bond is responsible for the attraction between water molecules?

Accepted Answer

Hydrogen bond

Question 6

What is the main reason ice floats on water?

Accepted Answer

Hydrogen bonds cause water molecules in ice to be more spread out, making ice less dense than liquid water.

Question 7

Which property of water allows a water strider to walk on the surface of a pond?

Accepted Answer

Cohesion

Question 8

Which of the following best describes a nonpolar covalent bond?

Accepted Answer

A bond in which electrons are shared equally between two atoms.

Question 9

In the formation of sodium chloride ($$NaCl$$), what happens to the sodium atom?

Accepted Answer

It loses an electron and becomes a cation.

Question 10

Which of the following correctly orders the types of chemical bonds from strongest to weakest in biological systems?

Accepted Answer

Covalent \u003e Ionic \u003e Hydrogen \u003e van der Waals

Question 11

Which of the following best describes the term 'functional group' in organic chemistry?

Accepted Answer

A specific group of atoms within a molecule that is responsible for certain chemical reactions of that molecule.

Question 12

Which functional group is responsible for the acidic properties of amino acids?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 13

Which of the following best explains why carbon can form such a wide variety of molecules?

Accepted Answer

Carbon can form four covalent bonds with other atoms, allowing for diverse molecular structures.

Question 14

Which of the following is a property of water that results from hydrogen bonding and is crucial for life on Earth?

Accepted Answer

High specific heat

Question 15

Which of the following best describes a hydrocarbon?

Accepted Answer

A molecule consisting only of carbon and hydrogen atoms.

Question 16

Which of the following is a real-world application of radioactive isotopes?

Accepted Answer

Using $$^{14}C to $$date ancient fossils.

Question 17

Which of the following best explains the importance of molecular shape in biology, as seen with morphine and endorphins?

Accepted Answer

Molecules with similar shapes can bind to the same receptors and produce similar biological effects.

Question 18

Which of the following statements about van der Waals interactions is correct?

Accepted Answer

They are weak attractions that can become significant when many such interactions occur simultaneously.

Question 19

Which of the following best describes the process of evaporation?

Accepted Answer

The transformation of a substance from liquid to gas as molecules gain enough energy to break free from the liquid's surface.

Question 20

Which of the following is NOT one of the four elements that make up 96% of living matter?

Accepted Answer

Calcium

The Chemical Context of Life: Study Notes for Cell Biology

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