Q: A sample of ice at $$0\ ^\circ\mathrm{C} is $$melted and then heated to $$50\ ^\circ\mathrm{C}. $$Which of the following equations would you use to calculate the total energy required for this process, assuming the mass of ice is $$m$$ grams, the heat of fusion is $$\Delta H_{fus}$$, and the specific heat of liquid water is $$c_{water}$$?

$$q = m \times \Delta H_{fus} + m \times c_{water} \times (50 - 0)$$

Q: A solution is prepared by dissolving 10 g of NaCl in 90 g of water. What is the mass percent concentration of NaCl in the solution?

$$\frac{10}{10+90} \times 100 = 10\%$$

Q: A 2.0 M NaCl solution is diluted to a final volume of 500 mL. If the initial volume was 100 mL, what is the final concentration?

$$M_1V_1 = M_2V_2 \implies M_2$ = \frac{2.0 \times 100}{500} = 0.40\ \mathrm{M}$$

Question 1

Which of the following best explains why water has a relatively high surface tension compared to most other liquids?

Accepted Answer

Water molecules form strong hydrogen bonds with each other, resulting in a greater cohesive force at the surface.

Question 2

A sample of ice at $$0\ ^\circ\mathrm{C} is $$melted and then heated to $$50\ ^\circ\mathrm{C}. $$Which of the following equations would you use to calculate the total energy required for this process, assuming the mass of ice is $$m$$ grams, the heat of fusion is $$\Delta H_{fus}$$, and the specific heat of liquid water is $$c_{water}$$?

Accepted Answer

$$q = m 	imes \Delta H_{fus} + m 	imes c_{water} 	imes (50 - 0)$$

Question 3

Which of the following compounds would exhibit hydrogen bonding as its strongest intermolecular force?

Accepted Answer

CH$$_3OH ($$methanol)

Question 4

A solution is prepared by dissolving 10 g of NaCl in 90 g of water. What is the mass percent concentration of NaCl in the solution?

Accepted Answer

$$\frac{10}{10+90} 	imes 100 = 10\%$$

Question 5

Which of the following best describes the process of osmosis?

Accepted Answer

The movement of solvent molecules through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Question 6

Which of the following statements about the solubility of gases in water is correct?

Accepted Answer

The solubility of gases in water decreases as temperature increases.

Question 7

Which of the following is an example of an ionic solid?

Accepted Answer

NaCl (sodium chloride)

Question 8

A 2.0 M NaCl solution is diluted to a final volume of 500 mL. If the initial volume was 100 mL, what is the final concentration?

Accepted Answer

$$M_1V_1 = M_2V_2 \implies M_2$ = \frac{2.0 	imes 100}{500} = 0.40\ \mathrm{M}$$

Question 9

Which of the following best explains why carbon can form such a large variety of organic compounds?

Accepted Answer

Carbon can form four covalent bonds, allowing for a variety of stable structures including chains, rings, and branches.

Question 10

Which of the following is the correct IUPAC name for the compound with the formula C$$_4H$_{10}$$?

Accepted Answer

Butane

Question 11

Which of the following best describes a saturated solution?

Accepted Answer

A solution in which the maximum amount of solute has dissolved at a given temperature.

Question 12

Which of the following functional groups is present in all amino acids?

Accepted Answer

Both an amino group ($$-\mathrm{NH}_2) $$and a carboxyl group ($$-\mathrm{COOH})$$

Question 13

Which of the following best describes the difference between a molecular solid and an ionic solid?

Accepted Answer

A molecular solid is composed of molecules held together by intermolecular forces, while an ionic solid is composed of ions held together by ionic bonds.

Question 14

Which of the following is a correct statement about nucleic acids?

Accepted Answer

Nucleic acids store and transmit genetic information in cells.

Question 15

A solution is made by dissolving 5.0 g of glucose (C$$_6H$_{12}O$_6) in $$enough water to make 100 mL of solution. What is the molarity of the solution? (Molar mass of glucose = 180 g/mol)

Accepted Answer

$$M = \frac{5.0\ \mathrm{g}}{180\ \mathrm{g/mol}} \div 0.100\ \mathrm{L} = 0.28\ \mathrm{M}$$

Question 16

Which of the following best describes a peptide bond?

Accepted Answer

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another.

Question 17

Which of the following statements about the boiling point elevation of a solution is correct?

Accepted Answer

The boiling point of a solution is higher than that of the pure solvent because the presence of solute particles disrupts the vaporization process.

Question 18

Which of the following is a correct classification for cholesterol?

Accepted Answer

Steroid (a type of lipid)

Question 19

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose sugar and is double-stranded, while RNA contains ribose sugar and is usually single-stranded.

Question 20

Which of the following best describes the role of carbohydrates in the body?

Accepted Answer

Carbohydrates are the primary source of energy for most cells.

Intro to Chemistry Midterm Exam Study Guide – Step-by-Step Guidance

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