Question 1

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

Accepted Answer

Electron

Question 2

An atom of oxygen has 6 valence electrons. How many covalent bonds is it most likely to form?

Accepted Answer

2

Question 3

Which of the following best describes the difference between polar and nonpolar covalent bonds?

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons due to differences in electronegativity, while nonpolar covalent bonds involve equal sharing.

Question 4

Given the electronegativity values: O = 3.5, H = 2.1, which type of bond forms between oxygen and hydrogen in a water molecule?

Accepted Answer

Polar covalent bond

Question 5

Which property of water allows insects to walk on its surface?

Accepted Answer

Surface tension

Question 6

Why does ice float on water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds hold water molecules further apart in the solid state.

Question 7

Which equation correctly represents the dissociation of water?

Accepted Answer

$$H_2O \rightarrow H^+ + OH^-$$

Question 8

A solution has a hydrogen ion concentration of $$[H^+] = 1 	imes 10$$^{-4}$$ M. What is its pH?

Accepted Answer

$$pH = 4$$

Question 9

Which of the following best explains why water is a good solvent for ionic compounds?

Accepted Answer

Water molecules are polar and can surround and separate positive and negative ions.

Question 10

Which statement about buffers is correct?

Accepted Answer

Buffers maintain a stable pH by neutralizing excess acids or bases.

Question 11

Which of the following is an example of a base?

Accepted Answer

Sodium hydroxide ($$NaOH)$$

Question 12

What is the main reason water has a high specific heat?

Accepted Answer

Hydrogen bonds between water molecules require more energy to break.

Question 13

Which property of water is most important for moderating Earth's climate?

Accepted Answer

High specific heat

Question 14

Which of the following best describes the difference between adhesion and cohesion?

Accepted Answer

Cohesion is the attraction between water molecules; adhesion is the attraction between water molecules and other substances.

Question 15

Which of the following solutions has the highest concentration of hydrogen ions?

Accepted Answer

pH 2

Question 16

If a solution has a pH of 7, what is the concentration of $$OH^-$$ ions?

Accepted Answer

$$1 	imes 10$$^{-7}$$ M

Question 17

Which of the following best explains why oil does not dissolve in water?

Accepted Answer

Oil molecules are nonpolar and do not interact favorably with polar water molecules.

Question 18

Which of the following is a correct definition of electronegativity?

Accepted Answer

The ability of an atom to attract electrons in a chemical bond.

Question 19

Which of the following best describes a buffer's role in blood?

Accepted Answer

Buffers keep blood pH constant by neutralizing excess acids and bases.

Question 20

Which of the following is a real-world example of a hydrophobic substance?

Accepted Answer

Olive oil

Lecture 4

Guida di studio - Domande di pratica

Study guide - Flashcard