Question 1

A student is tasked with determining the density of an unknown metal. She measures the mass as 45.2 g and the volume as 16.8 mL. Which of the following best represents the density, and what is the correct number of significant figures?

Accepted Answer

$$2.7\ \mathrm{g/mL}$$

Question 2

Which of the following statements about the atomic structure is correct according to modern quantum mechanical theory?

Accepted Answer

Electrons are found in defined energy levels but their exact position cannot be precisely known.

Question 3

A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is the empirical formula of this compound?

Accepted Answer

$$\mathrm{CH}_2\mathrm{O}$$

Question 4

Which of the following best describes a redox reaction?

Accepted Answer

A reaction in which electrons are transferred from one species to another.

Question 5

A sample of gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$300\ \mathrm{K}. $$What will be its volume at $$2.00\ \mathrm{atm}$$ and $$400\ \mathrm{K}$$, assuming ideal gas behavior?

Accepted Answer

$$1.67\ \mathrm{L}$$

Question 6

In a calorimetry experiment, $$50.0\ \mathrm{g} of $$water at $$25.0\ ^\circ\mathrm{C}$$ absorbs $$4180\ \mathrm{J} of $$heat. What is the final temperature of the water? (Specific heat of water $$= 4.18\ \mathrm{J/g\cdot ^\circ C})$$

Accepted Answer

$$35.0\ ^\circ\mathrm{C}$$

Question 7

Which of the following electron configurations represents a ground state atom of magnesium ($$Z=12$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 8

Which of the following elements has the highest first ionization energy?

Accepted Answer

Neon ($$\mathrm{Ne})$$

Question 9

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

$$\mathrm{CO}_2$$

Question 10

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$NaCl in $$100.0\ \mathrm{g} of $$water. What is the molality of the solution? ($$M_{\mathrm{NaCl}} = 58.44\ \mathrm{g/mol})$$

Accepted Answer

$$1.71\ \mathrm{mol/kg}$$

Question 11

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

Accepted Answer

Ice is less dense than liquid water because its molecules form an open hexagonal structure.

Question 12

Which of the following changes will shift the equilibrium of the reaction $$\mathrm{N}_2(g) + 3\mathrm{H}_2(g) \rightleftharpoons 2\mathrm{NH}_3(g) to $$the right?

Accepted Answer

Removing ammonia ($$\mathrm{NH}_3) as it $$forms.

Question 13

A student mixes $$50.0\ \mathrm{mL} of$$ $$0.100\ \mathrm{M}$$ AgNO$$_3$$ with $$50.0\ \mathrm{mL} of$$ $$0.100\ \mathrm{M}$$ NaCl$$. What mass of AgCl will precipitate? (M$$_{\mathrm{AgCl}} = 143.32\ \mathrm{g/mol}$)

Accepted Answer

$$0.358\ \mathrm{g}$$

Question 14

Which of the following best describes the intermolecular forces present in liquid ammonia ($$\mathrm{NH}_3$$)?

Accepted Answer

Hydrogen bonding, dipole-dipole, and London dispersion forces.

Question 15

A $$0.100\ \mathrm{m}$$ aqueous solution of a nonvolatile, nonelectrolyte solute freezes at $$-0.186\ ^\circ\mathrm{C}. $$What is the freezing point depression constant $$K_f$$ for water? (Freezing point of pure water $$= 0.00\ ^\circ\mathrm{C})$$

Accepted Answer

$$1.86\ ^\circ\mathrm{C\cdot kg/mol}$$

Question 16

Which of the following solids is best described as a metallic solid?

Accepted Answer

Sodium ($$\mathrm{Na})$$

Question 17

Which of the following statements about chemical equilibrium is correct?

Accepted Answer

At equilibrium, the rates of the forward and reverse reactions are equal.

Question 18

A $$1.00\ \mathrm{L}$$ solution contains $$0.10\ \mathrm{mol} of $$acetic acid ($$\mathrm{CH}_3\mathrm{COOH}) $$and $$0.10\ \mathrm{mol} of $$sodium acetate ($$\mathrm{CH}_3\mathrm{COONa}). If $$the $$K_a of $$acetic acid is $$1.8 	imes 10$$^{-5}$$, what is the pH of the solution? (Assume $$\log 1.8 \approx 0.26$$)

Accepted Answer

$$4.74$$

Question 19

Which of the following best explains why copper reacts with silver nitrate but not with sodium chloride in aqueous solution?

Accepted Answer

Copper is more reactive than silver but less reactive than sodium.

Question 20

Which of the following best describes the trend in atomic radius across a period in the periodic table?

Accepted Answer

Atomic radius decreases from left to right.

General Chemistry I: Course Schedule and Key Topics Overview

Guida di studio - Domande di pratica

Study guide - Flashcard