Question 1

Which of the following is the correct condensed electron configuration for a neutral lead atom ($$Z=82$$)?

Accepted Answer

$$[Xe] \ 4f$$^{14}$$ \ 5d$$^{10}$$ \ 6s$$^{2}$$ \ 6p$$^{2}$$

Question 2

Which of the following transitions in the hydrogen atom results in a negative $$\Delta E ($$energy is released by the atom)?

Accepted Answer

$$n=4 \rightarrow n=2$$

Question 3

How many unpaired electrons are present in a $$\mathrm{Cr$$^{3+}$$}$$ ion?

Accepted Answer

3

Question 4

What is the molecular geometry and approximate bond angle around the central atom in $$\mathrm{$$ClO_2$$^-}$$?

Accepted Answer

Bent, $$\approx 109.5^\circ$$

Question 5

Which of the following molecules or ions is polar?

Accepted Answer

$$\mathrm{$$PBr_3$$}$$

Question 6

A solution is prepared by dissolving 26.0 g of $$\mathrm{$$BaCl_2$$} in $$enough water to make 450.0 mL of solution. What is the molarity of the solution? ($$\mathrm{$$BaCl_2$$}$$ molar mass = 208.23 g/mol)

Accepted Answer

$$0.278\ \mathrm{M}$$

Question 7

What is the empirical formula of a compound that is 50.0% C, 5.6% H, and 44.4% O by mass?

Accepted Answer

$$\mathrm{C_3H_4O_2}$$

Question 8

Which of the following sets of quantum numbers is allowed for an electron in an atom?

Accepted Answer

$$n=3,\ l=2,\ m_l=0,\ m_s=+\frac{1}{2}$$

Question 9

A 5.0 g sample of copper cools from $$35.0^\circ\mathrm{C} to$$ $$22.6^\circ\mathrm{C}$$, releasing 23.6 J of heat. What is the specific heat capacity of copper?

Accepted Answer

$$0.36\ \mathrm{J\ g$$^{-1}$$\ ^\circ C$$^{-1}$$}$$

Question 10

Which of the following statements about atomic orbitals is FALSE?

Accepted Answer

For $$n=4$$, there are 3 d orbitals.

Question 11

What is the formal charge on the bromine atom in $$\mathrm{$$BrO_3$$^-}$$\,$$ if all three Br–O bonds are single bonds?

Accepted Answer

+2

Question 12

How many lone pairs are present in the Lewis structure of $$\mathrm{$$HNO_2$$} ($$skeleton HONO, all atoms have zero formal charge)?

Accepted Answer

4

Question 13

A sample of $$\mathrm{Cu(OH)_2} ($$molar mass = 97.56 g/mol) is formed by adding excess $$\mathrm{NaOH} to 1.35 L of$$ $$\mathrm{Cu$$^{2+}$$}$$ solution. If 14.2 g of $$\mathrm{Cu(OH)_2}$$ precipitate is collected, what was the initial concentration of $$\mathrm{Cu$$^{2+}$$} in $$the solution?

Accepted Answer

$$0.108\ \mathrm{M}$$

Question 14

Which of the following molecules or ions has a trigonal bipyramidal molecular geometry?

Accepted Answer

$$\mathrm{PF_5$}$$

Question 15

What is the wavelength (in nm) of light emitted when an electron in a hydrogen atom transitions from $$n=5 to$$ $$n=1$$? ($$R_H = 1.097 	imes 10^7$\ \mathrm{m}^{-1}$$, $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$95.0\ \mathrm{nm}$$

Question 16

A reaction produces 46.1 g of $$\mathrm{CF_2Cl_2}$$ from 72.9 g of $$\mathrm{$$CCl_4$$} ($$molar mass $$= 153.8\ \mathrm{g/mol}). If $$the theoretical yield is 56.4 g, what is the percent yield?

Accepted Answer

$$81.8\%$$

Question 17

Which of the following is the correct net ionic equation for the reaction between $$\mathrm{H_2SO_4}$$ and $$\mathrm{NaOH}$$?

Accepted Answer

$$2\mathrm{H^+}(aq) + 2\mathrm{OH^-}(aq) \rightarrow 2\mathrm{H_2O}(l)$$

Question 18

Which of the following is the correct molecular formula for a compound with 54.53% C, 9.15% H, and a molar mass of approximately 88 g/mol?

Accepted Answer

$$\mathrm{C_4H_8O_2}$$

Question 19

Which of the following reactions is a redox reaction, and what is oxidized?

Accepted Answer

$$\mathrm{Mg} + 2\mathrm{HCl} \rightarrow \mathrm{$$MgCl_2$$} + \mathrm{H_2$}$$; Mg is oxidized

Question 20

What is the heat evolved (in kJ) when 25.0 g of $$\mathrm{Na_2O_2}$$ reacts, given $$\Delta H^\circ = -126\ \mathrm{kJ}$$ for $$2\mathrm{Na_2O_2}$$?

Accepted Answer

$$-25.2\ \mathrm{kJ}$$

General Chemistry Study Guide: Electronic Structure, Bonding, Stoichiometry, Reactions, and Thermochemistry

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