Question 1

Which of the following statements best explains why water is an excellent solvent for ionic compounds such as table salt (NaCl)?

Accepted Answer

Water molecules form hydration spheres around ions due to their polar nature.

Question 2

A carbon atom has 6 protons and 6 neutrons. What is its atomic number and mass number, respectively?

Accepted Answer

Atomic number: $$6$$, Mass number: $$12$$

Question 3

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

Accepted Answer

Surface tension due to cohesion

Question 4

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between atoms.

Question 5

Which of the following elements is NOT one of the four major elements that make up 96% of the human body?

Accepted Answer

Calcium (Ca)

Question 6

A sodium atom loses an electron to form a sodium ion. What is the charge of the sodium ion and what type of bond does it form with a chloride ion?

Accepted Answer

Positive charge; ionic bond

Question 7

Which statement correctly describes the difference between polar and nonpolar covalent bonds?

Accepted Answer

Polar covalent bonds share electrons unequally; nonpolar covalent bonds share electrons equally.

Question 8

Which of the following molecules is hydrophobic and will NOT dissolve in water?

Accepted Answer

Triglyceride

Question 9

If an atom has 8 electrons in its outermost shell, what is true about its chemical reactivity?

Accepted Answer

It is chemically stable and unlikely to react.

Question 10

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

Accepted Answer

Ice is less dense than liquid water because its molecules form a crystal lattice.

Question 11

Which of the following is a trace element found in the human body?

Accepted Answer

Iron (Fe)

Question 12

What is the mass number of a carbon isotope with 6 protons and 8 neutrons?

Accepted Answer

$$14$$

Question 13

Which type of chemical bond is responsible for the structure of DNA and proteins?

Accepted Answer

Hydrogen bonds

Question 14

Which of the following best describes the role of water in chemical reactions within the body?

Accepted Answer

Water takes part in chemical reactions such as dehydration synthesis and hydrolysis.

Question 15

Which of the following molecules will form a hydration sphere when dissolved in water?

Accepted Answer

NaCl (table salt)

Question 16

Which of the following is true about covalent bonds?

Accepted Answer

They are strong and do not dissociate in water.

Question 17

Which of the following is an example of a molecule with a nonpolar covalent bond?

Accepted Answer

Molecular nitrogen ($$\mathrm{N_2$})$$

Question 18

Which property of water is most important for maintaining a constant body temperature in humans?

Accepted Answer

High specific heat

Question 19

Which of the following best describes hydrophilic molecules?

Accepted Answer

Molecules that mix with water and are polar.

Question 20

Which of the following is a correct statement about ions?

Accepted Answer

Ions are atoms that have gained or lost electrons and have an electrical charge.

Module 1: Chemistry of Life, Major Macromolecules, Membranes and the Cell

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