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

$$[H^+] = 10$$^{-4}$$ \text{ M}$$

Question 1

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

Accepted Answer

Water molecules are polar, allowing them to surround and stabilize both Na+ and Cl- ions through charge interactions.

Question 2

A scientist discovers a new atom with an atomic number of 8 and an atomic weight of 18. How many neutrons does this atom have?

Accepted Answer

$$18 - 8 = 10$$ neutrons

Question 3

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

Accepted Answer

A buffer prevents large, sudden changes in pH by accepting or donating H+ ions as needed.

Question 4

Which of the following is true regarding isotopes of an element?

Accepted Answer

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

Question 5

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

Accepted Answer

$$[H^+] = 10$$^{-4}$$ 	ext{ M}$$

Question 6

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

Accepted Answer

Hydrogen bonds in ice cause the molecules to be arranged in a lattice, making ice less dense than liquid water.

Question 7

Which of the following is a property of water that helps moderate Earth's climate and maintain stable temperatures in organisms?

Accepted Answer

Water has a high specific heat, requiring more energy to change its temperature.

Question 8

A molecule of methane ($$CH_4) is $$formed when carbon shares electrons equally with four hydrogen atoms. What type of bond is present between carbon and hydrogen in methane?

Accepted Answer

Nonpolar covalent bond

Question 9

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

A compound consists of two or more elements in a fixed ratio, while a mixture consists of elements and/or compounds in variable ratios.

Question 10

A solution contains $$0.5$$ moles of glucose dissolved in $$1$$ liter of water. What is the molarity of this solution?

Accepted Answer

$$0.5 M$$

Question 11

Which of the following best explains why nonpolar molecules, such as oils, do not dissolve in water?

Accepted Answer

Nonpolar molecules are hydrophobic and do not interact favorably with water's polar molecules.

Question 12

If the concentration of $$[OH^-] in a $$solution is $$10^{-9} M$$, what is the pH of the solution?

Accepted Answer

pH = 5

Question 13

Which of the following statements about hydrogen bonds is correct?

Accepted Answer

Hydrogen bonds are weak, reversible attractions between polar molecules or within large molecules.

Question 14

A student adds an acid to a neutral solution, causing the pH to drop from 7 to 5. By what factor has the hydrogen ion concentration increased?

Accepted Answer

100 times

Question 15

Which of the following best describes the relationship between atomic number and atomic weight?

Accepted Answer

Atomic number is the number of protons; atomic weight is the sum of protons and neutrons.

Question 16

Which of the following scenarios best illustrates the concept of surface tension in water?

Accepted Answer

A water strider insect walking on the surface of a pond without sinking.

Question 17

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation is positively charged, while an anion is negatively charged.

Question 18

Which of the following best explains why water has a high heat of vaporization?

Accepted Answer

A large amount of energy is required to break the hydrogen bonds between water molecules.

Question 19

A molecule of oxygen gas ($$O_2) is $$held together by a double covalent bond. How many pairs of electrons are shared between the two oxygen atoms?

Accepted Answer

2 pairs

Question 20

Which of the following best describes the chemical behavior of an atom with a full outer electron shell?

Accepted Answer

It is inert and unlikely to react with other atoms.

Atoms, Molecules, and Life: Foundations of Biological Chemistry

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드