Question 1

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of valence electrons between two atoms.

Question 2

A solution has a pH of 4. If the pH drops to 3, what happens to the concentration of hydrogen ions $$[H^+]$$?

Accepted Answer

It increases by a factor of 10.

Question 3

Which property of water allows it to move upward through the stem of a plant against gravity?

Accepted Answer

Cohesion and adhesion due to hydrogen bonding

Question 4

Which of the following statements about ionic bonds is correct?

Accepted Answer

Ionic bonds result from the attraction between oppositely charged ions.

Question 5

A molecule of water ($$H_2O) is $$described as a polar molecule. What does this mean?

Accepted Answer

The molecule has a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms.

Question 6

Which of the following best explains why table salt ($$NaCl) $$dissolves easily in water?

Accepted Answer

Water molecules surround and separate the sodium and chloride ions due to their polarity.

Question 7

Which element is most likely to form three covalent bonds based on its valence electrons?

Accepted Answer

Nitrogen ($$N)$$

Question 8

A patient is diagnosed with acidosis, a condition where blood pH drops below 7.35. What does this indicate about the $$[H^+]$$ concentration in the blood?

Accepted Answer

The $$[H^+]$$ concentration has increased, making the blood more acidic.

Question 9

Which of the following is a trace element required by humans in very small amounts?

Accepted Answer

Iron

Question 10

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 11

If an atom has an atomic number of 11 and a mass number of 23, how many neutrons does it have?

Accepted Answer

12

Question 12

Which of the following is an example of an intermolecular force?

Accepted Answer

Hydrogen bond between two water molecules

Question 13

Which of the following best explains why water has a high specific heat?

Accepted Answer

Hydrogen bonds between water molecules require a large amount of energy to break.

Question 14

A solution has a $$[H^+] of$$ $$1 	imes 10$$^{-9}$$ M. What is its pH?

Accepted Answer

$$pH = 9$$

Question 15

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons determine the chemical reactivity of an atom.

Question 16

Which of the following best describes a cation?

Accepted Answer

An atom that has lost electrons and has a positive charge.

Question 17

Which of the following is a real-life example of a polar covalent bond?

Accepted Answer

The bond between hydrogen and oxygen in a water molecule.

Question 18

A molecule has the formula $$C_6H_{12}O_6$. What is its molecular mass? (Atomic masses: C = 12$, H = 1$, O = 16$)

Accepted Answer

$$180$$

Question 19

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice create a lattice that is less dense than liquid water.

Question 20

Which of the following is true about the relationship between pH and $$[H^+]$$ concentration?

Accepted Answer

As pH increases, $$[H^+]$$ decreases.

Chemistry of Life: Foundations for General Biology (2))

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