Question 1

A sample of 10 g sodium bicarbonate ($$\mathrm{$$NaHCO_3$$}) $$reacts with excess hydrochloric acid ($$\mathrm{HCl}) at 1.0 $$atm and 20 °C. What is the volume of $$\mathrm{CO_2$}$$ gas produced? (Molar mass $$\mathrm{$$NaHCO_3$$} = 84.01 g/$$mol, $$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$}$$, $$PV = nRT)$$

Accepted Answer

$$2.9\ \mathrm{L}$$

Question 2

Which statement best explains Boyle’s Law using kinetic molecular theory?

Accepted Answer

If the volume is halved, the pressure must double because the same number of particles collides with half the surface area.

Question 3

According to Graham’s Law, if $$\mathrm{NH_3$}$$ and $$\mathrm{HCl}$$ are released into still air, how far will $$\mathrm{NH_3$}$$ have effused when $$\mathrm{HCl}$$ has diffused 1.00 meter? (Molecular weights: $$\mathrm{NH_3$} = 17.031$$, $$\mathrm{HCl} = 36.461)$$

Accepted Answer

$$1.46\ \mathrm{meters}$$

Question 4

Under which conditions do the ideal gas laws fail, and which equation describes gas behavior in these conditions?

Accepted Answer

At high pressure and low temperature; the van der Waals equation describes gas behavior.

Question 5

A gas expands from $$2.0\ \mathrm{L} to$$ $$6.0\ \mathrm{L} at $$constant temperature and external pressure of $$1.2\ \mathrm{atm}. $$What is the work done by the gas? ($$1\ \mathrm{L\cdot atm} = 101.3\ \mathrm{J})$$

Accepted Answer

$$-490\ \mathrm{J}$$

Question 6

For the reaction $$2\mathrm{CO} (g) + \mathrm{O_2$} (g) \rightarrow 2\mathrm{CO_2$} (g)$$ with $$\Delta H = -566\ \mathrm{kJ/mol}$$, what is $$\Delta E at$$ $$1\ \mathrm{atm}$$ and $$25\ ^\circ \mathrm{C}$$? ($$\Delta E = \Delta H - \Delta nRT$$, $$\Delta n = -1$$, $$R = 8.314\ \mathrm{J/mol\cdot K})$$

Accepted Answer

$$-563.5\ \mathrm{kJ/mol}$$

Question 7

A $$1.435\ \mathrm{g}$$ sample of naphthalene ($$\mathrm{C$$_{10}$$H_8$$}$$) is burned in a bomb calorimeter, raising the temperature from 20.28$$\ ^\circ \mathrm{C}$$ to 25.95$$\ ^\circ \mathrm{C}$$. The calorimeter constant is 10.17$$\ \mathrm{kJ/^	ext{C}}$$. What is the molar heat of combustion? (Molar mass = 128.2$$\ \mathrm{g/mol}$)

Accepted Answer

$$-5146\ \mathrm{kJ/mol}$$

Question 8

A $$5.4\ \mathrm{g}$$ specimen of peanuts is burned under a beaker containing $$466\ \mathrm{g} of $$water. The water warms from $$8.5\ ^\circ \mathrm{C} to$$ $$74.6\ ^\circ \mathrm{C}. $$What is the caloric value per $$1\ \mathrm{g} of $$peanuts? ($$C_{water} = 4.18\ \mathrm{J/g\cdot ^	ext{C}}$$, $$1\ \mathrm{food\ calorie} = 1000\ \mathrm{calories})$$

Accepted Answer

$$5.70\ \mathrm{calories}$$

Question 9

Which color of visible light corresponds to photons with the highest energy per photon?

Accepted Answer

Violet

Question 10

An electron falls from the 6th to the 3rd quantum level in a hydrogen atom. What is the wavelength of the emitted photon? ($$R_H = 1.10 	imes 10^7$\ \mathrm{m$$^{-1}$$}$$, $$\frac{1}{\lambda} = R_H (\frac{1}{n_f^2$} - \frac{1}{n_i^2$}))$$

Accepted Answer

$$1094\ \mathrm{nm}$$

Question 11

Which subatomic particle has both wavelike and particle-like characteristics?

Accepted Answer

Electron

Question 12

Why do the s, p, d, and f orbitals have different energies in multi-electron atoms, but not in hydrogen?

Accepted Answer

Because electrons in multi-electron atoms experience different levels of penetration and shielding, altering their energies.

Question 13

Which experiment demonstrated that electrons can have two spin values ($$m_s = +1/2 or$$ $$-1/2$$)?

Accepted Answer

Stern-Gerlach experiment

Question 14

Which atom is larger: Ne or Li? Why?

Accepted Answer

Li, because it has a lower effective nuclear charge.

Question 15

Arrange the following ions in order from largest to smallest: $$\mathrm{S$$^{2-}$$}$$, $$\mathrm{Cl^-}$$, $$\mathrm{K^+}$$, $$\mathrm{Ca$$^{2+}$$}.$$

Accepted Answer

$$\mathrm{S$$^{2-}$$} \u003e \mathrm{Cl^-} \u003e \mathrm{K^+} \u003e \mathrm{Ca$$^{2+}$$}$$

Question 16

Which atom has the greater ionization energy: B or Be? Why?

Accepted Answer

Be, because the 2s orbital is more penetrative and harder to remove an electron from.

Question 17

What is the trend for electron affinity when moving along a row of the periodic table?

Accepted Answer

Electron affinity becomes more exothermic (negative) toward the right end of a row.

Question 18

Which orbital has five subdivisions corresponding to $$m_l = -2, -1, 0, +1, +2$$?

Accepted Answer

3d orbital

Question 19

Which orbital is shaped like a dumbbell with an equatorial ring?

Accepted Answer

dz2 orbital

General Chemistry Exam 3 Review – Step-by-Step Study Guidance

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