Question 1

Which subatomic particle is responsible for the unique identity of an element, and how is this reflected in the periodic table?

Accepted Answer

Proton; the number of protons (atomic number) defines the element and is used to organize the periodic table.

Question 2

A carbon atom has 6 protons and 8 neutrons. What is its mass number, and how is this value represented in chemical notation?

Accepted Answer

Mass number is 14, represented as $$^{14}\mathrm{C}.$$

Question 3

Which statement best explains why the mass of electrons is considered negligible when calculating the atomic mass of an atom?

Accepted Answer

Electrons have a mass approximately 1/1836th that of a proton, making their contribution to atomic mass insignificant.

Question 4

Which type of chemical bond is formed when one atom donates an electron to another atom, resulting in the formation of oppositely charged ions?

Accepted Answer

Ionic bond

Question 5

What is the maximum number of electrons that can occupy the second electron shell of an atom?

Accepted Answer

$$8$$

Question 6

Which of the following molecules is held together by polar covalent bonds, resulting in partial charges on its atoms?

Accepted Answer

H$$_2O ($$water)

Question 7

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

Accepted Answer

$$4$$

Question 8

Which property of water allows it to dissolve ionic compounds such as NaCl (table salt)?

Accepted Answer

Water's polarity enables it to surround and stabilize ions through hydrogen bonding and dipole interactions.

Question 9

How many grams of glucose (C$$_6H$_{12}O$_6) $$are required to prepare 1 liter of a 1 M solution? (Atomic masses: C = 12, H = 1, O = 16)

Accepted Answer

$$180$$ grams

Question 10

Which statement best describes the difference between a nonpolar covalent bond and a polar covalent bond?

Accepted Answer

Nonpolar covalent bonds involve equal sharing of electrons between atoms with similar electronegativities, while polar covalent bonds involve unequal sharing due to differences in electronegativity.

Question 11

Which of the following best explains why water has a high surface tension?

Accepted Answer

Hydrogen bonds between water molecules create cohesive forces at the surface.

Question 12

Which of the following is a consequence of the law of conservation of mass in chemical reactions?

Accepted Answer

The total mass and energy in a closed system remain constant during a chemical reaction.

Question 13

Which of the following best describes a redox (oxidation-reduction) reaction?

Accepted Answer

A reaction in which one atom loses electrons (oxidation) and another gains electrons (reduction).

Question 14

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 15

Which of the following is true about hydrogen bonds in biological molecules?

Accepted Answer

Hydrogen bonds are weak interactions that help stabilize the structure of proteins and DNA.

Question 16

A solution has a pH of 2. Which of the following statements is correct?

Accepted Answer

The solution is acidic and has a high concentration of $$[H^+]$$ ions.

Question 17

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve a full outer shell of 8 electrons.

Question 18

Which of the following elements typically forms four covalent bonds in biological molecules?

Accepted Answer

Carbon

Question 19

What is the molarity (M) of a solution containing 0.5 moles of NaCl dissolved in 1 liter of water?

Accepted Answer

$$0.5 M$$

Ch 2 lecture

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드