Question 1

Which property of water allows it to climb up narrow tubes against gravity, as seen in plant xylem?

Accepted Answer

Capillary action

Question 2

Water has a high specific heat compared to many other substances. What is the biological significance of this property?

Accepted Answer

It helps organisms maintain stable internal temperatures despite environmental changes.

Question 3

Which equation correctly represents the relationship between pH and hydrogen ion concentration $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10}[H^+]$$

Question 4

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-5}$$ M. What is its pH?

Accepted Answer

pH = 5

Question 5

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

Accepted Answer

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

Question 6

Which of the following is NOT a property of water resulting from its polar nature and hydrogen bonding?

Accepted Answer

Ability to dissolve nonpolar substances

Question 7

A buffer solution contains a weak acid and its conjugate base. What happens when a small amount of strong acid is added to this buffer?

Accepted Answer

The conjugate base reacts with the added acid, minimizing the change in pH.

Question 8

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water molecules are polar and can form hydration shells around ions.

Question 9

Which of the following equations represents the dissociation of water into hydrogen and hydroxide ions?

Accepted Answer

$$H_2O \rightarrow H^+ + OH^-$$

Question 10

Which statement about acids and bases is correct?

Accepted Answer

Acids are proton donors and bases are proton acceptors.

Question 11

A lake is observed to resist rapid temperature changes during the summer. Which property of water is primarily responsible for this phenomenon?

Accepted Answer

High specific heat

Question 12

Which of the following is a consequence of water's high heat of vaporization for living organisms?

Accepted Answer

It allows organisms to cool themselves efficiently through evaporation.

Question 13

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

Accepted Answer

Buffers prevent changes in pH by neutralizing added acids or bases.

Question 14

If the concentration of hydroxide ions $$[OH^-] in a $$solution is $$1 	imes 10$$^{-7}$$ M, what is the pOH of the solution?

Accepted Answer

pOH = 7

Question 15

Which of the following is an example of water's adhesive property?

Accepted Answer

Water molecules sticking to the walls of a glass tube

Question 16

Which of the following best explains why water is critical for life on Earth?

Accepted Answer

Water's polar nature and hydrogen bonding give it unique properties essential for biological processes.

Question 17

A scientist adds a strong base to a buffered solution. What is the expected outcome?

Accepted Answer

The buffer will donate protons to neutralize the base, minimizing the pH change.

Question 18

Which of the following is true about the pH of most living cells?

Accepted Answer

It is usually around 7.0 to 7.4.

Question 19

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

Accepted Answer

A solution is a homogeneous mixture, while a mixture can be homogeneous or heterogeneous.

Question 20

Which of the following is a correct definition of an electrolyte?

Accepted Answer

A substance that forms ions in water and can conduct an electrical current.

Chapter 3 Notes

Guida di studio - Domande di pratica