Q: A photon of green light has a frequency of $$6.0 \times 10$$^{14}$$\ \mathrm{s}^{-1}. $$What is its energy in joules?

$$3.98 \times 10$$^{-19}$$\ \mathrm{J}$$

Question 1

A sample of 10 g of sodium bicarbonate ($$\mathrm{$$NaHCO_3$$}) $$reacts completely with excess hydrochloric acid ($$\mathrm{HCl}) at$$ $$1.0$$ atm and $$20\ ^\circ\mathrm{C}. $$How many liters of carbon dioxide ($$\mathrm{CO_2$}) $$gas are produced? (Molar mass of $$\mathrm{$$NaHCO_3$$} = 84\ \mathrm{g/mol}$$, $$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$1.09\ \mathrm{L}$$

Question 2

Which of the following is NOT a postulate of the kinetic molecular theory of gases?

Accepted Answer

Gas particles exert attractive and repulsive forces on each other.

Question 3

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

Accepted Answer

$$486\ \mathrm{J}$$

Question 4

Which law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases, and how does kinetic molecular theory explain this?

Accepted Answer

Dalton's Law; because gas particles act independently and their collisions are additive.

Question 5

If ammonia ($$\mathrm{NH_3$}) $$and hydrogen chloride ($$\mathrm{HCl}) $$are released at opposite ends of a tube, how far will $$\mathrm{NH_3$}$$ have effused when $$\mathrm{HCl}$$ has diffused $$1.00\ \mathrm{m}$$? (Molar masses: $$\mathrm{NH_3$} = 17\ \mathrm{g/mol}$$, $$\mathrm{HCl} = 36.5\ \mathrm{g/mol})$$

Accepted Answer

$$1.47\ \mathrm{m}$$

Question 6

Under which conditions do the assumptions of the ideal gas law fail, and which equation better describes real gas behavior under these conditions?

Accepted Answer

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

Question 7

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

Accepted Answer

$$6.0\ \mathrm{food\ calories/g}$$

Question 8

A photon of green light has a frequency of $$6.0 	imes 10$$^{14}$$\ \mathrm{s}^{-1}. $$What is its energy in joules?

Accepted Answer

$$3.98 	imes 10$$^{-19}$$\ \mathrm{J}$$

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 $$n=6 to $$the $$n=3$$ quantum level in a hydrogen atom. What is the wavelength of the emitted photon? ($$R_H = 1.097 	imes 10^7$\ \mathrm{m}^{-1})$$

Accepted Answer

$$1094\ \mathrm{nm}$$

Question 11

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($$l)$$

Question 12

Which of the following sets of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$$n=2,\ l=2,\ m_l=0,\ m_s=+1/2$$

Question 13

Which atom in each pair is larger, and why? a) Ne and Li b) Li and Rb c) F and P

Accepted Answer

a) Li (fewer protons, less pull), b) Rb (more shells), c) P (lower effective nuclear charge)

Question 14

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 15

Which two factors most strongly affect the effective nuclear charge ($$Z_{\mathrm{eff}}) $$experienced by an electron in a multi-electron atom?

Accepted Answer

The number of protons and the amount of electron shielding

Question 16

Why does the atomic radius decrease steadily across the second and third rows of the periodic table, but remains nearly constant across the transition metals of the fourth row?

Accepted Answer

Because electrons are added to inner d orbitals, which do not shield effectively, so the nuclear charge increases but the size does not.

Question 17

Which atom has the highest first ionization energy among the following: Li, Be, B, C, N, O, F, Ne?

Accepted Answer

Ne

Question 18

Which subatomic particle exhibits both wavelike and particle-like properties?

Accepted Answer

Electron

Question 19

Why do the s, p, d, and f orbitals have different energies in multi-electron atoms, even though the hydrogen atom's energy levels depend only on $$n$$?

Accepted Answer

Electron-electron repulsions and shielding cause subshells to split in energy.

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