Question 1

Which of the following best describes a compound?

Accepted Answer

A substance formed by two or more elements combined in a fixed ratio.

Question 2

Which subatomic particle is responsible for the chemical behavior of an atom?

Accepted Answer

Electron

Question 3

What property of water allows it to dissolve many substances, making it an effective solvent in biological systems?

Accepted Answer

Its ability to form hydrogen bonds

Question 4

Which of the following is true about elements in biological systems?

Accepted Answer

Most living matter is made of four main elements: C, O, N, H.

Question 5

A molecule of sodium chloride (NaCl) is held together by which type of chemical bond?

Accepted Answer

Ionic bond

Question 6

Which of the following best explains why water is essential for life?

Accepted Answer

Water can form hydrogen bonds, allowing it to act as a universal solvent.

Question 7

Which statement correctly compares atoms, molecules, and compounds?

Accepted Answer

Compounds are made of molecules, which are made of atoms.

Question 8

If a solution has a pH of 4, which of the following statements is true?

Accepted Answer

The solution is acidic and has a high concentration of hydrogen ions.

Question 9

Which formula correctly relates the pH of a solution to the concentration of hydrogen ions $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10} [H^+]$$

Question 10

Which of the following best describes a buffer in a biological system?

Accepted Answer

A substance that maintains a stable pH by neutralizing acids and bases.

Question 11

Which of the following is a trace element important for biological function?

Accepted Answer

Zinc

Question 12

A cell is considered the lowest structural level capable of performing all activities of life because:

Accepted Answer

It is formed by combinations of compounds and molecules.

Question 13

Which of the following best explains the difference between hydrophilic and hydrophobic substances?

Accepted Answer

Hydrophilic substances dissolve in water, while hydrophobic substances do not.

Question 14

Which of the following is true about the distribution of electrons in the electron shells of atoms?

Accepted Answer

The chemical behavior of an atom is determined by the distribution of electrons in the electron shells.

Question 15

Which of the following is a correct statement about molecules?

Accepted Answer

Molecules can be formed from the same or different elements held together by covalent bonds.

Question 16

Which of the following is NOT a property of acids?

Accepted Answer

They increase the concentration of $$OH^-$$ ions in solution.

Question 17

A solution contains $$[H^+] = 1 	imes 10$$^{-7}$$ M. What is its pH?

Accepted Answer

$$pH = 7$$

Question 18

Which of the following best describes the role of hydrogen bonds in water?

Accepted Answer

They form between water molecules, giving water its unique properties.

Question 19

Which of the following is a correct statement about the periodic table and biological elements?

Accepted Answer

Only a small subset of elements are essential for life, with C, O, N, and H being the most abundant.

Question 20

Which of the following scenarios best illustrates the concept of a buffer in action?

Accepted Answer

A solution that resists changes in pH when small amounts of acid or base are added.

Lecture 2 Slides

Guida di studio - Domande di pratica