Question 1

Which of the following statements best explains why water is considered a polar molecule?

Accepted Answer

The oxygen atom in water is partially negative $$(\delta^-)$$ and the hydrogen atoms are partially positive $$(\delta^+)$$, resulting in an unequal sharing of electrons.

Question 2

A patient is diagnosed with anemia due to a mutation that changes the number of protons in the iron atoms of their hemoglobin. What is the most accurate description of this change?

Accepted Answer

The iron atoms have become different elements.

Question 3

Which of the following best describes the octet rule as it applies to chemical bonding?

Accepted Answer

Atoms are most stable when their outermost electron shell contains eight electrons.

Question 4

A solution is made by dissolving sodium chloride (NaCl) in water. In this scenario, which statement is correct?

Accepted Answer

Water is the solvent and NaCl is the solute.

Question 5

Which of the following is a property of hydrogen bonds that is essential for life?

Accepted Answer

They are responsible for the high surface tension of water.

Question 6

A chemical reaction is represented as $$AB \rightarrow A + B. $$What type of reaction is this, and what is a typical characteristic?

Accepted Answer

It is a decomposition (catabolic) reaction; it usually releases energy.

Question 7

Which of the following best describes an isotope?

Accepted Answer

An atom with the same number of protons but a different number of neutrons as another atom.

Question 8

Which of the following factors will increase the rate of a chemical reaction according to collision theory?

Accepted Answer

Adding a catalyst to lower the activation energy.

Question 9

A molecule of glucose $$(C_6H_{12}O_6$) is $$classified as which of the following?

Accepted Answer

An organic compound because it contains carbon bonded to hydrogen.

Question 10

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic bond?

Accepted Answer

Sodium donates an electron to chlorine, resulting in oppositely charged ions that attract each other.

Question 11

Which of the following is true regarding acids and bases in water?

Accepted Answer

An acid increases the concentration of hydrogen ions $$(H^+) in $$solution.

Question 12

A scientist is studying a reaction where $$A + B \rightarrow AB$$ and notes that energy is absorbed from the surroundings. What type of reaction is this?

Accepted Answer

Endergonic reaction

Question 13

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy, increasing the reaction rate.

Question 14

Which of the following is a correct statement about the atomic number of an element?

Accepted Answer

It is equal to the number of protons in the nucleus.

Question 15

A solution with a high concentration of $$H^+$$ ions has which of the following properties?

Accepted Answer

It is acidic and has a low pH.

Question 16

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electron pairs between atoms.

Question 17

Which of the following is an example of a suspension?

Accepted Answer

Blood, because its cells settle out if left undisturbed.

Question 18

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons determine how an atom interacts with other atoms.

Question 19

A radioactive isotope is used in medical imaging. What property makes it useful for this purpose?

Accepted Answer

It emits energy as radiation, which can be detected by imaging equipment.

Question 20

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

Accepted Answer

Oil is nonpolar and water is polar, so oil cannot form hydrogen bonds with water.

Atoms, Elements, Chemical Bonds, and Water: Foundations for Anatomy & Physiology

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