Q: A sample contains $$2.65$$ mol of oxalic acid ($$\mathrm{H_2C_2O_4}). $$How many hydrogen atoms are present in this sample?

$$2 \times 2.65 \times 6.022 \times 10$$^{23}$$ atoms

Q: What is the energy (in J) of a photon released when an electron in a hydrogen atom falls from $$n=5 to$$ $$n=1$$? ($$E_n = -2.18 \times 10$$^{-18}$$\ \mathrm{J}\ /\ n^2$)

$$2.09 \times 10$$^{-18}$$\ \mathrm{J}$$

Question 1

Which of the following is the correct systematic name for the compound with the formula $$\mathrm{Fe_2$(SO_4$)_3}$$?

Accepted Answer

Iron(III) sulfate

Question 2

A sample contains $$2.65$$ mol of oxalic acid ($$\mathrm{H_2C_2O_4}). $$How many hydrogen atoms are present in this sample?

Accepted Answer

$$2 	imes 2.65 	imes 6.022 	imes 10$$^{23}$$ atoms

Question 3

What is the molarity of a solution prepared by dissolving $$5.00 g of $$NaCl in enough water to make $$250.0 mL of $$solution? ($$M_{\mathrm{NaCl}} = 58.44\ \mathrm{g/mol})$$

Accepted Answer

$$0.342\ \mathrm{M}$$

Question 4

Which of the following pairs of elements is ranked correctly in order of increasing atomic radius?

Accepted Answer

Sn \u003c Ru \u003c Rb

Question 5

A $$100.0 mL $$sample of $$1.36 M $$NaBr(aq) has a density of $$1.129 g/mL. $$What is the mass percent of NaBr in this solution? ($$M_{\mathrm{NaBr}} = 102.89\ \mathrm{g/mol})$$

Accepted Answer

$$12.4\%$$

Question 6

Which of the following sets of quantum numbers is invalid, and why?

Accepted Answer

$$n=2,\ l=2,\ m_l=0,\ m_s=+\frac{1}{2}$$;\ l$$ cannot equal n$

Question 7

A solution is prepared by mixing $$100.0 mL of$$ $$0.256 M $$NaBr, $$200.0 mL of$$ $$0.685 M $$MgCl$$_2$$, and $$300.0 mL of$$ $$0.125 M $$AlBr$$_3. $$What is the final molarity of Br$$^-$$ ions in the mixture?

Accepted Answer

$$0.138\ \mathrm{M}$$

Question 8

Which of the following bonds has the highest percent ionic character?

Accepted Answer

K–F

Question 9

What is the energy (in J) of a photon released when an electron in a hydrogen atom falls from $$n=5 to$$ $$n=1$$? ($$E_n = -2.18 	imes 10$$^{-18}$$\ \mathrm{J}\ /\ n^2$)

Accepted Answer

$$2.09 	imes 10$$^{-18}$$\ \mathrm{J}$$

Question 10

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

Accepted Answer

O

Question 11

A $$100.0 mL $$sample of $$0.526 M $$LiF is diluted to $$0.129 M. $$What volume of water must be added?

Accepted Answer

$$300.0 mL$$

Question 12

Which of the following is the correct net ionic equation for the reaction between Na$$_2CO$_3(aq) $$and NiCl$$_2(aq$$)?

Accepted Answer

$$\mathrm{CO_3$^{2-}(aq) + Ni$$^{2+}$$(aq) \rightarrow $$NiCO_3$$(s)}$$

Question 13

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

Accepted Answer

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

Question 14

Which of the following ions has the largest ionic radius?

Accepted Answer

O$$^{2-}$$

Question 15

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$\mathrm{(NH_4$)_2SO_4}$$

Question 16

Which of the following best explains the anomaly in first ionization energy between Zn and Ga?

Accepted Answer

Ga has a lower first ionization energy than Zn because the added electron enters a higher energy p-orbital, which is less tightly held.

Question 17

Which of the following bonds is ranked correctly in order of increasing percent covalent character?

Accepted Answer

K–F \u003c K–S \u003c K–Se \u003c K–K

Question 18

A $$12.5 g $$sample of propane ($$\mathrm{C_3H_8}) $$reacts with $$51.0 g of$$ $$\mathrm{O_2$} to $$form $$\mathrm{CO_2$}$$ and $$\mathrm{H_2O}. If $$only $$7.22 g of$$ $$\mathrm{CO_2$} is $$formed, what is the percent yield?

Accepted Answer

$$22.2\%$$

Question 19

Which of the following elements has the highest electronegativity?

Accepted Answer

P

General Chemistry Study Guide: Nomenclature, Conversions, and Solution Concentrations

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