Question 1

Which of the following best explains why sunflowers can be used to clean up soils contaminated with heavy metals such as lead and zinc?

Accepted Answer

Sunflowers absorb heavy metals into their tissues, a process known as phytoremediation.

Question 2

Which statement correctly describes the difference between atomic number and mass number?

Accepted Answer

Atomic number is the number of protons; mass number is the sum of protons and neutrons.

Question 3

A neutral atom of potassium (K) has an atomic number of 19 and a mass number of 39. How many neutrons does it have? Use the formula $$	ext{Number of neutrons} = 	ext{Mass number} - 	ext{Atomic number}.$$

Accepted Answer

20

Question 4

Which of the following is an example of an isotope?

Accepted Answer

A carbon atom with 6 protons and 8 neutrons

Question 5

Which type of bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Question 6

What property of water allows a spider to walk on its surface, as shown in the image?

Accepted Answer

Surface tension due to cohesion among water molecules

Question 7

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

Accepted Answer

Hydrogen bonds in ice are more ordered, making ice less dense than liquid water.

Question 8

Which of the following is a real-world application of radioactive isotopes?

Accepted Answer

Dating fossils using carbon-14

Question 9

A sodium atom transfers an electron to a chlorine atom, resulting in the formation of NaCl. What type of bond is formed between sodium and chlorine?

Accepted Answer

Ionic bond

Question 10

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

Accepted Answer

Oil molecules are nonpolar and hydrophobic, so they do not interact with water.

Question 11

Which property of water is most responsible for the transport of water from roots to leaves in plants?

Accepted Answer

Cohesion and adhesion due to hydrogen bonding

Question 12

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

Accepted Answer

Acids increase the H$$^+$$ concentration in water.

Question 13

A solution has a pH of 5. What does this indicate about the solution?

Accepted Answer

It is acidic.

Question 14

Which of the following best describes a buffer in biological systems?

Accepted Answer

A substance that minimizes changes in H$$^+$$ and OH$$^-$$ concentrations.

Question 15

Which of the following is an example of a weak chemical interaction important in biological molecules?

Accepted Answer

Hydrogen bond

Question 16

Which of the following best explains why geckos can walk on walls?

Accepted Answer

Geckos use van der Waals interactions between tiny hairs on their feet and the wall surface.

Question 17

Which of the following is true about elements and compounds?

Accepted Answer

Compounds consist of two or more elements in a fixed ratio.

Question 18

Which of the following best describes the behavior of electrons in an atom?

Accepted Answer

Electrons are found in shells around the nucleus and have potential energy based on their distance from the nucleus.

Question 19

Which of the following is a correct statement about hydrogen bonds?

Accepted Answer

Hydrogen bonds occur when a hydrogen atom covalently bonded to an electronegative atom is attracted to another electronegative atom.

Chapter 2: The Chemical Context of Life – Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드