Q: A student is asked to prepare 250 mL of a 0.10 M NaCl solution from a solid sample. What mass of NaCl (molar mass = 58.44 g/mol) should the student weigh out?

$$0.250 \text{ L} \times 0.10 \text{ mol/L} \times 58.44 \text{ g/mol} = 1.46 g$$

Q: A solution is prepared by dissolving 10.0 g of glucose ($$C_6H_{12}O_6$, molar mass = 180.16 g/mol) in enough water to make 500 mL of solution. What is the molarity of the solution?

$$\frac{10.0 \text{ g}}{180.16 \text{ g/mol}} = 0.0555 \text{ mol}; \frac{0.0555 \text{ mol}}{0.500 \text{ L}} = 0.111 M$$

Q: A sample of gas occupies 2.0 L at 1.0 atm and 300 K. What will be its volume at 2.0 atm and 300 K, assuming ideal gas behavior?

$$V_2$$ = $$V_1$$ \times \frac{$$P_1$$}{$$P_2$$} = 2.0 \times \frac{1.0}{2.0} = 1.0$$ L

Question 1

Which of the following statements best explains why water is an effective solvent for many ionic compounds in biological systems?

Accepted Answer

Water molecules are polar, allowing them to surround and stabilize ions through ion-dipole interactions.

Question 2

A student is asked to prepare 250 mL of a 0.10 M NaCl solution from a solid sample. What mass of NaCl (molar mass = 58.44 g/mol) should the student weigh out?

Accepted Answer

$$0.250 	ext{ L} 	imes 0.10 	ext{ mol/L} 	imes 58.44 	ext{ g/mol} = 1.46 g$$

Question 3

Which of the following best describes the difference between ionic and covalent compounds?

Accepted Answer

Ionic compounds are formed by transferring electrons, while covalent compounds are formed by sharing electrons.

Question 4

A chemical reaction in a living cell releases heat to its surroundings. Which term best describes this reaction?

Accepted Answer

Exothermic

Question 5

A solution is prepared by dissolving 10.0 g of glucose ($$C_6H_{12}O_6$, molar mass = 180.16 g/mol) in enough water to make 500 mL of solution. What is the molarity of the solution?

Accepted Answer

$$\frac{10.0 	ext{ g}}{180.16 	ext{ g/mol}} = 0.0555 	ext{ mol}; \frac{0.0555 	ext{ mol}}{0.500 	ext{ L}} = 0.111 M$$

Question 6

Which of the following functional groups is present in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 7

A buffer solution is important in biological systems because it:

Accepted Answer

Maintains a relatively constant pH by neutralizing small amounts of added acid or base.

Question 8

Which of the following best describes the process of dilution when preparing a solution for a medical application?

Accepted Answer

Adding solvent to decrease the concentration, using $$C_1V_1 = C_2V_2 to $$calculate the required volumes.

Question 9

Which of the following is the correct IUPAC name for the compound with the structure $$CH_3CH_2CH_2OH$$?

Accepted Answer

Propanol

Question 10

A patient receives an intravenous (IV) solution that is isotonic to blood plasma. What property of the solution ensures it is safe for the patient?

Accepted Answer

It has the same osmotic pressure as blood, preventing net movement of water into or out of blood cells.

Question 11

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have similar chemical properties due to similar valence electron configurations.

Question 12

A chemical reaction has the following balanced equation: $$2H_2 + O_2$ \rightarrow 2H_2O. If 4.0 $$mol of $$H_2$$ and 2.0 mol of $$O_2$$ are mixed, what is the limiting reactant?

Accepted Answer

$$O_2$$

Question 13

Which of the following best describes the role of enzymes in metabolic pathways?

Accepted Answer

Enzymes lower the activation energy, increasing the rate of biochemical reactions.

Question 14

A sample of gas occupies 2.0 L at 1.0 atm and 300 K. What will be its volume at 2.0 atm and 300 K, assuming ideal gas behavior?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$P_1$$}{$$P_2$$} = 2.0 	imes \frac{1.0}{2.0} = 1.0$$ L

Question 15

Which of the following is a correct statement about acids and bases according to the Brønsted-Lowry definition?

Accepted Answer

An acid is a substance that donates a proton ($$H^+$$), and a base is a substance that accepts a proton.

Question 16

Which of the following best explains why lipids are insoluble in water?

Accepted Answer

Lipids are nonpolar molecules and do not interact favorably with polar water molecules.

Question 17

A food sample is analyzed using calorimetry and found to release 5000 J of heat when burned. If the sample has a mass of 2.0 g, what is its caloric value in kcal/g? ($$1 	ext{ cal} = 4.184 	ext{ J}$$, $$1 	ext{ kcal} = 1000 	ext{ cal})$$

Accepted Answer

$$\frac{5000 	ext{ J}}{4.184 	ext{ J/cal}} = 1195 	ext{ cal}; \frac{1195 	ext{ cal}}{1000} = 1.195 	ext{ kcal}; \frac{1.195 	ext{ kcal}}{2.0 	ext{ g}} = 0.60 	ext{ kcal/g}$$

Question 18

Which of the following is the correct order of increasing strength for the intermolecular forces present in organic molecules?

Accepted Answer

London dispersion \u003c Dipole-dipole \u003c Hydrogen bonding

Question 19

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

Accepted Answer

The sequence of amino acids linked by peptide bonds.

CHEM 107: Chemistry of Life – Structured Study Guide and Syllabus Overview

Guida di studio - Domande di pratica

Study guide - Flashcard