Question 1

Which of the following best describes the first law of thermodynamics?

Accepted Answer

Energy is never created nor destroyed, only transformed.

Question 2

A reaction is carried out in a series of steps. According to Hess's Law, what is true about the enthalpy change for the overall reaction?

Accepted Answer

It is the sum of the enthalpy changes for each individual step.

Question 3

Which equation correctly relates the change in internal energy ($\Delta E$), heat ($q$), and work ($w$)?

Accepted Answer

$\Delta E = q + w$

Question 4

A gas is collected over water at 25°C. The total pressure is 755 mmHg and the vapor pressure of water at 25°C is 24 mmHg. What is the pressure of the dry gas?

Accepted Answer

731 mmHg

Question 5

Which of the following statements about the photoelectric effect is correct?

Accepted Answer

Electrons are emitted only if the light has enough energy, regardless of intensity.

Question 6

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($l$)

Question 7

Which element has the highest electronegativity?

Accepted Answer

Fluorine

Question 8

What is the effect of electron shielding on the effective nuclear charge ($Z_{eff}$) experienced by valence electrons?

Accepted Answer

It decreases $Z_{eff}$.

Question 9

Which of the following intermolecular forces is the strongest?

Accepted Answer

Hydrogen bonding

Question 10

A sample of gas occupies 10.0 L at 2.00 atm and 300 K. What will be its volume at 1.00 atm and 300 K? (Assume ideal gas behavior.)

Accepted Answer

20.0 L

Question 11

Which of the following best explains why water has a higher boiling point than expected for its molar mass?

Accepted Answer

Water forms hydrogen bonds.

Question 12

Which of the following is the correct expression for the energy of a photon?

Accepted Answer

$E = h 
u$

Question 13

Which of the following molecules would have the highest boiling point?

Accepted Answer

NH$_3$

Question 14

Which of the following best describes the difference between sigma ($\sigma$) and pi ($\pi$) bonds?

Accepted Answer

$\sigma$ bonds are stronger than $\pi$ bonds and are formed by head-to-head overlap.

Question 15

Which of the following is true about the atomic radius as you move across a period from left to right?

Accepted Answer

It decreases due to increasing effective nuclear charge.

Question 16

A 100 g sample of water is heated from 25°C to 75°C. If the specific heat of water is $4.18 \ \mathrm{J/g \cdot ^\circ C}$, how much heat is absorbed?

Accepted Answer

$20,900 \ \mathrm{J}$

Question 17

Which of the following best describes why noble gases are generally unreactive?

Accepted Answer

They have filled valence shells.

Question 18

Which of the following is the correct van der Waals equation for real gases?

Accepted Answer

$\left( P + \frac{a n^2}{V^2} \right) (V - nb) = nRT$

Question 19

Which of the following best explains why the boiling point of a liquid increases with increasing intermolecular forces?

Accepted Answer

More energy is required to separate the molecules.

General Chemistry Study Notes: Thermochemistry, Quantum Mechanics, Periodic Properties, Gases, Bonding, Intermolecular Forces, and Solutions

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