Question 1

Which of the following best explains why water (H$$_2O) is a $$polar molecule?

Accepted Answer

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

Question 2

Which type of bond is formed when one atom donates an electron to another atom, resulting in oppositely charged ions that attract each other?

Accepted Answer

Ionic bond

Question 3

Methane (CH$$_4) is $$considered nonpolar because:

Accepted Answer

The electronegativity difference between carbon and hydrogen is small, resulting in equal sharing of electrons.

Question 4

Which property of water allows it to moderate Earth's climate by resisting rapid temperature changes?

Accepted Answer

High specific heat capacity

Question 5

A solution has a hydrogen ion concentration of $$[H^+] = 1 	imes 10$$^{-5}$$ M. What is its pH?

Accepted Answer

$$5$$

Question 6

Which of the following best describes a hydrogen bond?

Accepted Answer

An attraction between a partially positive hydrogen atom and a partially negative atom (such as oxygen or nitrogen) in another molecule.

Question 7

Why does ice float on liquid water?

Accepted Answer

Ice is less dense than liquid water due to the hydrogen-bonded lattice structure.

Question 8

Which of the following substances would most likely dissolve in water?

Accepted Answer

Sodium chloride (NaCl)

Question 9

If a solution has a pH of 3, what is the concentration of hydrogen ions $$[H^+] in $$the solution?

Accepted Answer

$$1 	imes 10$$^{-3}$$ M

Question 10

Which of the following statements about acids and bases is correct?

Accepted Answer

An acid donates $$H^+$$ ions, while a base accepts or depletes $$H^+$$ ions.

Question 11

Which of the following best describes van der Waals interactions?

Accepted Answer

Weak attractions between molecules due to transient regions of partial positive and negative charges.

Question 12

A molecule with a large difference in electronegativity between its atoms is most likely to form which type of bond?

Accepted Answer

Polar covalent bond

Question 13

Which of the following is a real-life consequence of water's high surface tension?

Accepted Answer

Small insects can walk on the surface of a pond without sinking.

Question 14

If the pH of a solution changes from 7 to 5, how does the hydrogen ion concentration change?

Accepted Answer

It increases by 100 times.

Question 15

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

Accepted Answer

Oil molecules are nonpolar and cannot form hydrogen bonds with water.

Question 16

A patient is diagnosed with acidosis, meaning their blood pH is below 7.4. Which of the following is true about their blood?

Accepted Answer

The concentration of $$[H^+] is $$higher than normal.

Question 17

Which of the following is an example of a double covalent bond?

Accepted Answer

The bond between the two oxygen atoms in O$$_2$$

Question 18

Which property of water is most important for the transport of nutrients and waste in living organisms?

Accepted Answer

Water's ability to dissolve many substances due to its polarity

Question 19

A student mixes ammonia (NH$$_3) $$with water and observes that the pH increases. What is the best explanation for this observation?

Accepted Answer

Ammonia acts as a base and removes $$H^+$$ ions from the solution.

Question 20

Which of the following best describes the relationship between electronegativity and bond polarity?

Accepted Answer

The greater the difference in electronegativity between two atoms, the more polar the bond.

Chapter 2: Chemistry – Chemical Bonds, Electronegativity, and Water Properties

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