Question 1

Which property of water allows insects to walk on its surface, and what is the molecular basis for this property?

Accepted Answer

Surface tension; water molecules are held together by hydrogen bonds

Question 2

A patient’s blood pH is measured at 7.2. According to the pH scale, which condition does this indicate and what are the possible consequences?

Accepted Answer

Acidosis; risk of coma or death

Question 3

Which of the following best distinguishes a mixture from a compound?

Accepted Answer

Mixtures are physically blended, while compounds are chemically combined

Question 4

Which type of mixture in the body is characterized by particles that are too large to pass through semipermeable membranes, scatter light, and remain permanently mixed?

Accepted Answer

Colloid

Question 5

If a solution has a pH of 4, how many times greater is its hydrogen ion concentration compared to a solution with pH 6?

Accepted Answer

$$10^2 = 100$

Question 6

Which property of water is most important for metabolic reactions in the body, and why?

Accepted Answer

Solvency; it allows substances to dissolve and react

Question 7

A blood sample separates into plasma and cells after standing. What type of mixture does this represent?

Accepted Answer

Suspension

Question 8

Which of the following best describes hydrophilic substances?

Accepted Answer

They are polarized or charged and dissolve in water

Question 9

What is the role of buffers in biological systems?

Accepted Answer

Buffers resist changes in pH

Question 10

Which of the following is true about the pH scale?

Accepted Answer

A solution with pH 6 is more acidic than a solution with pH 8

Question 11

Which property of water allows it to reduce friction around organs by adhering to large membranes?

Accepted Answer

Adhesion

Question 12

Which of the following is NOT a property of a solution?

Accepted Answer

Solute particles scatter light

Question 13

A mixture of oil and vinegar in salad dressing is best classified as which type of mixture?

Accepted Answer

Emulsion

Question 14

Which of the following best explains why water is called the 'universal solvent'?

Accepted Answer

It dissolves a wide variety of substances due to its polarity

Question 15

Which of the following is a correct statement about acids and bases?

Accepted Answer

Acids release $$H^+$$ ions in water

Question 16

If a patient’s blood pH rises above 7.45, what condition is present and what is a possible outcome?

Accepted Answer

Alkalosis; risk of physiological dysfunction

Question 17

Which of the following best describes the difference between hydrophobic and hydrophilic molecules?

Accepted Answer

Hydrophobic molecules are nonpolar and do not dissolve in water; hydrophilic molecules are polarized or charged and dissolve in water

Question 18

Which property of water is most responsible for its ability to support life by maintaining stable temperatures in organisms?

Accepted Answer

Thermal stability

Question 19

Which of the following is true about colloids in the body?

Accepted Answer

Colloids scatter light and are usually cloudy

Question 20

A solution contains $$10^{-5}$$ moles of $$H^+$$ per liter. What is its pH?

Accepted Answer

$$pH = 5$$

Chapter 2: Chemistry of Life: Water and Mixtures

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