Q: A solution has a pH of 3. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-3}$$ \text{ M}$$

Q: If the concentration of $$[OH^-] in a $$solution is $$1 \times 10$$^{-10}$$ \text{ M}$$, what is the concentration of $$[H^+]$$?

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

Question 1

Which of the following statements best describes the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells possess a nucleus that encloses their DNA, whereas prokaryotic cells lack a nucleus and have DNA in the cytoplasm.

Question 2

Which property of water allows it to move upward against gravity in plant stems?

Accepted Answer

Adhesion, which is the attraction between water molecules and other substances.

Question 3

A solution has a pH of 3. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-3}$$ 	ext{ M}$$

Question 4

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

Accepted Answer

Hydrogen bonds in ice create a lattice structure that makes ice less dense than liquid water.

Question 5

Which of the following is a consequence of water’s high specific heat for living organisms?

Accepted Answer

Water’s temperature remains relatively stable, helping organisms maintain homeostasis.

Question 6

A buffer solution contains carbonic acid ($$H_2CO_3) $$and its conjugate base ($$HCO_3$$^-$$). If a strong acid is added to this solution, what will happen?

Accepted Answer

The $$HCO_3$$^-$$ will accept H$$^+$$ ions, minimizing the change in pH.

Question 7

Which type of chemical bond is responsible for the weak, temporary attraction between water molecules?

Accepted Answer

Hydrogen bond

Question 8

If the concentration of $$[OH^-] in a $$solution is $$1 	imes 10$$^{-10}$$ 	ext{ M}$$, what is the concentration of $$[H^+]$$?

Accepted Answer

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

Question 9

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally due to differences in electronegativity.

Question 10

A student mixes salt ($$NaCl) in $$water and observes that it dissolves completely. Which property of water is responsible for this?

Accepted Answer

Water’s polarity enables it to surround and separate ions, dissolving the salt.

Question 11

Which of the following is true about the pH scale?

Accepted Answer

A solution with pH 8 is basic, while a solution with pH 2 is acidic.

Question 12

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

Accepted Answer

Hydrogen bonds between water molecules require significant energy to break before vaporization can occur.

Question 13

Which of the following is NOT a property of water that supports life?

Accepted Answer

Low specific heat

Question 14

A solution has a pH of 8. Is this solution acidic, basic, or neutral?

Accepted Answer

Basic

Question 15

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers maintain a stable pH by absorbing or donating $$H^+$$ ions.

Question 16

Which of the following is the correct formula for calculating pH from hydrogen ion concentration?

Accepted Answer

$$	ext{pH} = -\log([H^+])$$

Question 17

Which of the following is the correct relationship between $$[H^+]$$ and $$[OH^-] in $$pure water at 25°C?

Accepted Answer

$$[H^+] 	imes [OH^-] = 1 	imes 10$$^{-14}$$

Question 18

Which of the following best describes surface tension in water?

Accepted Answer

It is the result of hydrogen bonds creating a strong film at the liquid’s surface.

Question 19

Which of the following is a real-world consequence of water’s expansion upon freezing?

Accepted Answer

Ice forms on the surface of lakes, insulating the water below and protecting aquatic life.

Question 20

Which of the following best explains why water is considered the ‘solvent of life’?

Accepted Answer

Water’s polarity allows it to dissolve and hydrate a wide variety of molecules.

Introduction to Biology and Water Chemistry: Study Notes

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