Question 1

During alcoholic fermentation, yeast converts glucose to ethanol and carbon dioxide according to the equation: $$\mathrm{C_6H_{12}O_6$\ (aq) \rightarrow 2\ C_2H_5OH\ (aq) + 2\ CO_2$\ (g)}. If 9.07 g of $$glucose reacts, what is the percent yield of ethanol if 4.60 g of ethanol is collected?

Accepted Answer

72.5%

Question 2

A 5.00 L flask contains 4.0 g of gas at 298 K. Flask A is filled with $$\mathrm{O_2$}$$, Flask B with $$\mathrm{CH_4$}$$, and Flask C with $$\mathrm{CO_2$}. $$Which flask has the greatest number of moles of gas?

Accepted Answer

Flask B ($$\mathrm{CH_4$})$$

Question 3

Which of the following statements best explains why $$\mathrm{CH_4$}$$ effuses faster than $$\mathrm{N_2$}$$ through a tiny hole at the same temperature?

Accepted Answer

Because $$\mathrm{CH_4$}$$ has a lower molar mass than $$\mathrm{N_2$}$$

Question 4

A compound has an empirical formula of $$\mathrm{SF_2$}. At 298 K$$, 0.198 g of the gaseous compound occupies a volume of 221 mL and exerts a pressure of 1.02 atm. What is the molecular formula of the gas?

Accepted Answer

$$\mathrm{S_2F_4}$$

Question 5

Given the reaction $$\mathrm{7\ $$NaN_3$$\ (s) \rightarrow 3\ Na_2SiO_3\ (s) + 2\ $$SiO_2$$\ (s) + 9\ N_2$\ (g)}$$, how many grams of $$\mathrm{$$NaN_3$$}$$ are required to produce 10.0 L of $$\mathrm{N_2$}$$ gas at STP?

Accepted Answer

19.2 g

Question 6

Which of the following best describes the difference between heat capacity and specific heat capacity?

Accepted Answer

Heat capacity is an extensive property, while specific heat capacity is an intensive property.

Question 7

What is the energy (in kJ/mol) associated with light of wavelength 350 nm?

Accepted Answer

$$\mathrm{E = 571\ kJ/mol}$$

Question 8

How many $$d-$$orbitals are there in an atom? Explain in terms of quantum numbers.

Accepted Answer

There are 5 $$d-$$orbitals, corresponding to $$m_l = -2, -1, 0, +1, +2$$

Question 9

Which of the following electron configurations describes the valence electrons in sodium?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^1$$

Question 10

Which of the following elements has the largest atomic radius?

Accepted Answer

Na

Question 11

Which of the following molecules is capable of hydrogen bonding among themselves?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 12

Which of the following best explains why water has a higher boiling point than methane?

Accepted Answer

Water forms hydrogen bonds, which are stronger than London dispersion forces present in methane

Question 13

Which of the following is the correct Lewis structure for $$\mathrm{CO_2$}$$?

Accepted Answer

$$\mathrm{O=C=O}$$ with two lone pairs on each O

Question 14

Which of the following best describes the difference between molecular orbital theory and valence bond theory?

Accepted Answer

Molecular orbital theory describes electrons as delocalized over the entire molecule, while valence bond theory describes electrons as localized between atoms.

Question 15

Which of the following compounds would you expect to have the highest boiling point?

Accepted Answer

$$\mathrm{CH_3CH_2OH}$$

Question 16

Which of the following phase changes occurs when the pressure of benzene is reduced from 1 atm to 0.1 atm at 80°C?

Accepted Answer

Liquid to gas

Question 17

Which of the following is the correct condensed ground state electron configuration for iron (Fe)?

Accepted Answer

$$[Ar]\ 4s^2$\ 3d^6$

Question 18

Which of the following best describes the shape and hybridization of the carbon atom in methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

Tetrahedral, $$sp^3$$

Question 19

Which of the following is the correct formula for calculating the root mean square velocity ($$u_{rms}) of a $$gas molecule?

Accepted Answer

$$u_{rms} = \sqrt{\frac{3RT}{M}}$$

General Chemistry Final Exam Study Guide: Key Topics and Concepts

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