Question 1

Which of the following statements best describes the internal energy ($$U) of a $$system?

Accepted Answer

It is the sum of the potential and kinetic energies of the component molecules.

Question 2

Which one of the following is an endothermic process?

Accepted Answer

Melting ice

Question 3

Calculate the value of $$\Delta H$$ for the reaction below, given the enthalpies of formation: $$\mathrm{2H_2(g) + O_2$(g) \rightarrow 2H_2O(l)}$$; $$\Delta H_f^\circ(\mathrm{H_2O(l)}) = -286\ \mathrm{kJ/mol}.$$

Accepted Answer

$$-572\ \mathrm{kJ}$$

Question 4

A coffee-cup calorimeter contains 100.0 g of water at $$22.0\ ^\circ\mathrm{C}. $$When 4.18 g of NaCl is dissolved, the temperature drops to $$20.5\ ^\circ\mathrm{C}. $$What is the enthalpy change ($$q) $$for the dissolution process? ($$c = 4.18\ \mathrm{J/g\cdot K})$$

Accepted Answer

$$-627\ \mathrm{J}$$

Question 5

Which of the following statements about bond enthalpy is correct?

Accepted Answer

Bond enthalpy is always positive because energy is required to break bonds.

Question 6

Given the reaction $$\mathrm{CH_4$(g) + 2O_2(g) \rightarrow CO_2$(g) + 2H_2O(l)}$$ and $$\Delta H = -890.3\ \mathrm{kJ}$$, how much heat is released when 16.0 g of methane is combusted?

Accepted Answer

$$-890.3\ \mathrm{kJ}$$

Question 7

Which of the following molecules has the largest London dispersion forces?

Accepted Answer

$$\mathrm{C_6H_{14}}$$

Question 8

What is the hybridization of the central carbon atom in $$\mathrm{CO_2$}$$?

Accepted Answer

$$sp$$

Question 9

Which of the following molecules is polar?

Accepted Answer

$$\mathrm{H_2O}$$

Question 10

A sample of gas at $$1.00\ \mathrm{atm}$$ and $$273\ \mathrm{K}$$ occupies $$22.4\ \mathrm{L}. $$What is the molar mass of the gas if 44.8 g occupies this volume?

Accepted Answer

$$44.8\ \mathrm{g/mol}$$

Question 11

Which of the following best describes the shape of $$\mathrm{SF_6$}$$ according to VSEPR theory?

Accepted Answer

Octahedral

Question 12

Which of the following molecules would have the lowest boiling point?

Accepted Answer

$$\mathrm{CH_4$}$$

Question 13

Which of the following is the best Lewis structure for $$\mathrm{$$OCl_2$$}$$?

Accepted Answer

O with two single bonds to Cl, and two lone pairs on O

Question 14

Which of the following is true for a process at constant volume?

Accepted Answer

$$q = \Delta U$$ and $$\Delta H = \Delta U + P\Delta V$$

Question 15

Which of the following molecules is expected to have bond angles of approximately $$109.5^\circ$$?

Accepted Answer

$$\mathrm{CH_4$}$$

Question 16

Which of the following is the correct order of decreasing F–C–F angle in the compounds below?
I. $$\mathrm{BF_2$}
II$$. $$\mathrm{CF_2$}$$
III. $$\mathrm{CF_4$}$$

Accepted Answer

I \u003e II \u003e III

Question 17

Which of the following is paramagnetic?

Accepted Answer

$$\mathrm{O_2$}$$

Question 18

Which of the following molecules is most likely to exhibit hydrogen bonding?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 19

Which of the following is the maximum number of covalent bonds that can be formed between two atoms?

Accepted Answer

3

Question 20

Which of the following is the correct electron configuration for $$\mathrm{Fe$$^{2+}$$}$$?

Accepted Answer

$$[\mathrm{Ar}]\ 3d^6$

General Chemistry Practice Exam Study Guide: Thermochemistry, Bonding, Gases, and Molecular Structure

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