Question 1

A chemical reaction occurs in a closed system and releases 250 J of heat to the surroundings while the system does 100 J of work on the surroundings. What is the change in internal energy ($$\Delta E) of $$the system?

Accepted Answer

$$\Delta E = -350\ \mathrm{J}$$

Question 2

Which of the following best describes an isolated system?

Accepted Answer

A system that cannot exchange heat or mass with its surroundings

Question 3

Which of the following statements about state functions is correct?

Accepted Answer

The value of a state function depends only on the current state of the system, not on the path taken to reach that state.

Question 4

A reaction is carried out in a bomb calorimeter and the temperature of the water increases by $$2.5\ ^\circ\mathrm{C}. If $$the heat capacity of the calorimeter is $$5.00\ \mathrm{kJ}/^\circ\mathrm{C}$$, what is the heat of the reaction ($$q_{rxn}$$)?

Accepted Answer

$$q_{rxn} = -12.5\ \mathrm{kJ}$$

Question 5

Which energy source provides the largest percentage of energy in the United States, according to the pie chart?

Accepted Answer

Petroleum

Question 6

Which of the following equations correctly relates the speed of light ($$c$$), wavelength ($$\lambda$$), and frequency ($$
u) of $$electromagnetic radiation?

Accepted Answer

$$c = \lambda 
u$$

Question 7

Which region of the electromagnetic spectrum has the shortest wavelength?

Accepted Answer

Gamma rays

Question 8

According to the Bohr model, what happens when an electron in a hydrogen atom moves from $$n=3 to$$ $$n=1$$?

Accepted Answer

A photon is emitted and the atom releases energy.

Question 9

Which quantum number defines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 10

How many total orbitals are present in the $$n=3$$ shell?

Accepted Answer

9

Question 11

Which of the following electron configurations represents a nitrogen atom (atomic number 7)?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^3$$

Question 12

Which of the following statements is a consequence of the Pauli Exclusion Principle?

Accepted Answer

No two electrons in the same atom can have the same set of four quantum numbers.

Question 13

Which of the following is the correct condensed electron configuration for sodium (Na, atomic number 11)?

Accepted Answer

[Ne] $$3s^1$$

Question 14

A sample of glucose ($$C_6H_{12}O_6$) is combusted in a calorimeter. If 10.0 g of glucose is burned and the enthalpy of combustion is -2803$$\ \mathrm{kJ/mol}$$, how much energy is released?

Accepted Answer

$$-155.7\ \mathrm{kJ}$$

Question 15

Which of the following best describes the difference between core electrons and valence electrons?

Accepted Answer

Core electrons are in filled inner shells, while valence electrons are in the outermost shell.

Question 16

Which of the following statements about the energy of orbitals in multi-electron atoms is correct?

Accepted Answer

Orbitals in the same shell are not always degenerate due to electron-electron repulsion.

Question 17

Which of the following is the correct order of increasing wavelength for the following types of electromagnetic radiation: infrared, ultraviolet, radio waves?

Accepted Answer

Ultraviolet \u003c Infrared \u003c Radio waves

Question 18

If a system absorbs 500 J of heat from the surroundings and has 200 J of work done on it by the surroundings, what is the sign and value of $$\Delta E$$?

Accepted Answer

$$+700\ \mathrm{J}$$

Question 19

Which of the following best describes the process of energy conversion in photosynthesis?

Accepted Answer

Sunlight is converted to chemical energy in green plants.

Thermochemistry and Electronic Structure of Atoms: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard