Q: Which of the following is a correct example of an exchange (displacement) reaction?

$$\text{AB} + \text{CD} \rightarrow \text{AD} + \text{CB}$$

Question 1

Which of the following best describes the difference between kinetic and potential energy in the context of muscle contraction?

Accepted Answer

Potential energy is stored in the chemical bonds of ATP, and kinetic energy is released as muscles contract and move the skeleton.

Question 2

A solution contains 5 grams of glucose (molecular weight = 180 g/mol) dissolved in enough water to make 1 liter. What is the molarity (M) of this solution? Use the formula $$M = \frac{	ext{moles of solute}}{	ext{liters of solution}}.$$

Accepted Answer

$$0.028\ M$$

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 4

Which of the following mixtures is best described as a colloid?

Accepted Answer

Jell-O

Question 5

A patient is given a radioactive isotope for imaging. Which property of radioisotopes makes them useful for this purpose?

Accepted Answer

They emit energy that can be detected by scanners as they decay.

Question 6

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

Accepted Answer

Water forms hydration layers around ions due to its polarity, allowing ionic compounds to dissociate.

Question 7

Which of the following is a correct example of an exchange (displacement) reaction?

Accepted Answer

$$	ext{AB} + 	ext{CD} ightarrow 	ext{AD} + 	ext{CB}$$

Question 8

Which of the following best describes the role of enzymes in chemical reactions?

Accepted Answer

Enzymes lower the activation energy, allowing reactions to proceed more rapidly.

Question 9

A patient’s arterial blood pH drops to 6.8 during cardiac arrest. What is the most likely consequence for enzyme function?

Accepted Answer

Enzymes will denature, losing their functional shape and activity.

Question 10

Which of the following statements about ATP is correct?

Accepted Answer

ATP provides immediate, usable energy for cellular work by transferring a phosphate group.

Question 11

Which of the following best explains why saturated fats are solid at room temperature while unsaturated fats are liquid?

Accepted Answer

Saturated fats have only single bonds, allowing molecules to pack closely together.

Question 12

Which of the following is a function of prostaglandins (a type of eicosanoid)?

Accepted Answer

They play a role in inflammation and blood clotting.

Question 13

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in a polypeptide chain.

Question 14

Which of the following is a correct complementary base pairing in DNA?

Accepted Answer

Adenine pairs with thymine.

Question 15

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

Accepted Answer

Hydrogen bonding between water molecules allows it to absorb and release heat slowly.

Question 16

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$moles per liter? Use the formula $$pH = -\log_{10}[H^+].$$

Accepted Answer

$$1 	imes 10$$^{-4}$$\ 	ext{M}$$

Question 17

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

Accepted Answer

Compounds are always homogeneous, while mixtures can be homogeneous or heterogeneous.

Question 18

Which of the following is a property of phospholipids that is critical for cell membrane structure?

Accepted Answer

They have both hydrophilic heads and hydrophobic tails, allowing them to form bilayers.

Question 19

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

Accepted Answer

Buffers resist changes in pH by binding or releasing hydrogen ions.

Question 20

Which of the following is true about the quaternary structure of proteins?

Accepted Answer

It describes the interaction between two or more polypeptide chains to form a functional protein.

Chapter 2: Chemistry Comes Alive – Study Notes

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