Q: A sample of gas is heated at constant pressure, causing its temperature to increase from 300 K to 350 K. If the initial volume is 2.00 L, what is the final volume of the gas? (Assume ideal gas behavior.)

$$V_2$$ = $$V_1$$ \times \frac{$$T_2$$}{$$T_1$$} = 2.00\ \mathrm{L} \times \frac{350\ \mathrm{K}}{300\ \mathrm{K}} = 2.33\ \mathrm{L}$$

Q: A chemical reaction occurs in a bomb calorimeter containing 1.50 g of substance. The temperature of the calorimeter increases by 2.00 $$^{\circ}C. If $$the heat capacity of the calorimeter is 5.00 J/$$^{\circ}C$$, what is the heat released by the reaction?

$$q = C \Delta T = 5.00\ \mathrm{J}$$/^{\circ}$$\mathrm{C} \times 2.00\ ^{\circ}\mathrm{C} = 10.0\ \mathrm{J}$$

Q: What is the frequency of light with a wavelength of $$500\ \mathrm{nm}$$? (Speed of light $$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$\nu = \frac{c}{\lambda} = \frac{3.00 \times 10^8$\ \mathrm{m/s}}{5.00 \times 10$$^{-7}$$\ \mathrm{m}} = 6.00 \times 10$$^{14}$$\ \mathrm{s}^{-1}$$

Q: A photon has a frequency of $$5.00 \times 10$$^{14}$$\ \mathrm{Hz}. $$What is its energy?

$$E = h\nu = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s} \times 5.00 \times 10$$^{14}$$\ \mathrm{Hz} = 3.31 \times 10$$^{-19}$$\ \mathrm{J}$$

Question 1

A sample of gas is heated at constant pressure, causing its temperature to increase from 300 K to 350 K. If the initial volume is 2.00 L, what is the final volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$T_2$$}{$$T_1$$} = 2.00\ \mathrm{L} 	imes \frac{350\ \mathrm{K}}{300\ \mathrm{K}} = 2.33\ \mathrm{L}$$

Question 2

Which of the following statements about endothermic and exothermic reactions is correct?

Accepted Answer

In an endothermic reaction, the system absorbs heat from the surroundings, resulting in $$q \u003e 0.$$

Question 3

A chemical reaction occurs in a bomb calorimeter containing 1.50 g of substance. The temperature of the calorimeter increases by 2.00 $$^{\circ}C. If $$the heat capacity of the calorimeter is 5.00 J/$$^{\circ}C$$, what is the heat released by the reaction?

Accepted Answer

$$q = C \Delta T = 5.00\ \mathrm{J}$$/^{\circ}$$\mathrm{C} 	imes 2.00\ ^{\circ}\mathrm{C} = 10.0\ \mathrm{J}$$

Question 4

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

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Question 5

Calculate the change in internal energy $$\Delta U$$ for a system that absorbs 50.0 J of heat and does 20.0 J of work on the surroundings.

Accepted Answer

$$\Delta U = q + w = 50.0\ \mathrm{J} + (-20.0\ \mathrm{J}) = 30.0\ \mathrm{J}$$

Question 6

Which of the following transitions in the hydrogen atom emits a photon with the largest energy?

Accepted Answer

$$n = 3 \rightarrow n = 1$$

Question 7

Which of the following colors of visible light has the longest wavelength?

Accepted Answer

Red

Question 8

What is the frequency of light with a wavelength of $$500\ \mathrm{nm}$$? (Speed of light $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$
u = \frac{c}{\lambda} = \frac{3.00 	imes 10^8$\ \mathrm{m/s}}{5.00 	imes 10$$^{-7}$$\ \mathrm{m}} = 6.00 	imes 10$$^{14}$$\ \mathrm{s}^{-1}$$

Question 9

Which quantum numbers are possible for a 4f orbital?

Accepted Answer

$$n = 4,\ l = 3$$

Question 10

Which of the following elements has the ground state electron configuration $$[\mathrm{Ar}]4s^23$d^104p^5$?

Accepted Answer

Br

Question 11

Which of the following statements about effective nuclear charge ($$Z_{\mathrm{eff}}) is $$TRUE?

Accepted Answer

$$Z_{\mathrm{eff}}$$ increases across a period from left to right.

Question 12

Which of the following is NOT a standard state?

Accepted Answer

Aqueous HCl at 1 M

Question 13

A photon has a frequency of $$5.00 	imes 10$$^{14}$$\ \mathrm{Hz}. $$What is its energy?

Accepted Answer

$$E = h
u = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s} 	imes 5.00 	imes 10$$^{14}$$\ \mathrm{Hz} = 3.31 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 14

Which of the following electron configurations is correct for carbon?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^2$$

Question 15

Which of the following best explains why atomic radius decreases across a period?

Accepted Answer

Increasing effective nuclear charge pulls electrons closer to the nucleus.

Question 16

Which of the following quantum numbers represents the orientation of an orbital in space?

Accepted Answer

$$m_l$$

Question 17

A reaction has $$\Delta H = -100\ \mathrm{kJ}$$ and $$\Delta S = -200\ \mathrm{J/K}. At $$what temperature does the reaction become nonspontaneous? ($$\Delta G = \Delta H - T\Delta S)$$

Accepted Answer

$$T \u003e 500\ \mathrm{K}$$

Question 18

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

Accepted Answer

Electrons are ejected from a metal surface only if the incident light has a frequency above a threshold value.

Question 19

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

Accepted Answer

Neon

Question 20

Which of the following is the correct set of quantum numbers for the last electron added to aluminum ($$Z = 13$$)?

Accepted Answer

$$n = 3,\ l = 1,\ m_l = -1,\ m_s = +\frac{1}{2}$$

General Chemistry Exam 3 Study Guide: Thermochemistry, Quantum Mechanics, and Periodic Properties

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