Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \ \mathrm{M}$$

Question 1

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

Accepted Answer

Because there is an unequal sharing of electrons, resulting in a partial negative charge near the oxygen and a partial positive charge near the hydrogens.

Question 2

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \ \mathrm{M}$$

Question 3

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

Accepted Answer

A substance that minimizes changes in pH by accepting or donating hydrogen ions.

Question 4

A radioactive isotope of carbon, $$^{14}C$$, is used in medical imaging. Which of the following statements about $$^{14}C is $$correct?

Accepted Answer

$$^{14}C$$ has 6 protons and 8 neutrons.

Question 5

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

Accepted Answer

Because the positive and negative ions in salt are attracted to the partial charges of the polar water molecules.

Question 6

A scientist mixes 10 grams of glucose in 100 mL of water. In this solution, which term best describes glucose?

Accepted Answer

Solute

Question 7

Which of the following is an example of evaporative cooling in real life?

Accepted Answer

Sweating during exercise, where water evaporates from the skin and removes heat from the body.

Question 8

Which of the following best describes the difference between an ionic bond and a covalent bond?

Accepted Answer

Ionic bonds involve the transfer of electrons from one atom to another, while covalent bonds involve the sharing of electrons between atoms.

Question 9

A molecule of methane ($$CH_4) is $$held together by which type of bond?

Accepted Answer

Nonpolar covalent bonds

Question 10

Which of the following statements about trace elements is correct?

Accepted Answer

Trace elements are required in minute amounts but are essential for proper physiological functioning.

Question 11

If a solution has a pH of 9, which of the following best describes the solution?

Accepted Answer

It is basic and has a low concentration of $$H^+$$ ions.

Question 12

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

Accepted Answer

Surface tension due to hydrogen bonding

Question 13

Which of the following best describes the role of buffers in human blood?

Accepted Answer

Buffers prevent drastic changes in pH by neutralizing excess acids or bases.

Question 14

Which of the following is a product in the chemical reaction: $$2H_2 + O_2$ \rightarrow 2H_2O$$?

Accepted Answer

$$H_2O$$

Question 15

Ocean acidification is primarily caused by which of the following processes?

Accepted Answer

Absorption of excess atmospheric $$CO_2 by $$seawater, forming carbonic acid.

Question 16

Which of the following best describes the atomic number of an element?

Accepted Answer

The number of protons in the nucleus.

Question 17

A beaker contains a solution with a solute concentration of 0.1 M. If you add more solute to the beaker, which of the following will occur?

Accepted Answer

The solution will become more concentrated.

Question 18

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

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds hold water molecules in a lattice that is more spread out.

Question 19

Which of the following is an example of a chemical reaction?

Accepted Answer

Burning wood to produce carbon dioxide and water.

Question 20

Which of the following best describes electronegativity?

Accepted Answer

The ability of an atom to attract electrons in a chemical bond.

Essential Chemistry Vocabulary for General Biology

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드