Q: Which of the following is the correct expression for the enthalpy change of a reaction using bond energies?

$\Delta H = \sum D_{\text{bonds broken}} - \sum D_{\text{bonds formed}}$

Q: Which of the following is the correct formula for calculating the formal charge on an atom in a Lewis structure?

$\text{Formal charge} = \text{valence electrons} - (\text{lone pairs} + \frac{1}{2} \times \text{bonding electrons})$

Q: Which of the following is the correct expression for the standard enthalpy change of a reaction using enthalpies of formation?

$\Delta H^\circ_{rxn} = \sum \Delta H^\circ_f(\text{products}) - \sum \Delta H^\circ_f(\text{reactants})$

Question 1

Which of the following statements best describes the difference between the molecular geometry and the electron domain geometry of a molecule?

Accepted Answer

Molecular geometry considers only the arrangement of atoms, while electron domain geometry considers both atoms and lone pairs around the central atom.

Question 2

Given the reaction: $\mathrm{CaCO_3(s) + 2HCl(aq) \rightarrow CaCl_2(aq) + CO_2(g) + H_2O(l)}$, how many liters of $\mathrm{CO_2}$ gas at 0.875 atm and 31°C can be produced from 10.0 g of $\mathrm{CaCO_3}$? (R = 0.0821 L·atm·mol$^{-1}$·K$^{-1}$, Molar mass of $\mathrm{CaCO_3}$ = 100.1 g/mol)

Accepted Answer

$2.98$ L

Question 3

Which of the following compounds is expected to have a molecular dipole moment?

Accepted Answer

$\mathrm{ICL_3}$

Question 4

A sample of He gas (2.0 mmol) effuses through a pinhole in 53 s. The same amount of an unknown gas effuses in 246 s. What is the molar mass of the unknown gas?

Accepted Answer

$85.5$ g/mol

Question 5

Which of the following best describes the effect of increasing temperature on the solubility of most solid ionic compounds in water?

Accepted Answer

Solubility increases with increasing temperature.

Question 6

What is the frequency (in Hz) of electromagnetic radiation with a wavelength of $361.3$ nm? (Speed of light $c = 2.9979 	imes 10^8$ m/s)

Accepted Answer

$8.295 	imes 10^{14}$ Hz

Question 7

Which of the following is the correct net ionic equation for the reaction between $\mathrm{K_3PO_4(aq)}$ and $\mathrm{AgNO_3(aq)}$?

Accepted Answer

$\mathrm{PO_4^{3-}(aq) + 3Ag^+(aq) \rightarrow Ag_3PO_4(s)}$

Question 8

Which of the following statements about the molecular orbital diagram for $\mathrm{NO}$ is correct?

Accepted Answer

$\mathrm{NO}$ has one unpaired electron and is paramagnetic.

Question 9

A solution is prepared by mixing 70.0 mL of 0.100 mol/L HCl and 30.0 mL of 0.200 mol/L NaCl. What is the molarity of chloride ion in the final solution?

Accepted Answer

$0.130$ mol/L

Question 10

Which of the following is the correct expression for the enthalpy change of a reaction using bond energies?

Accepted Answer

$\Delta H = \sum D_{	ext{bonds broken}} - \sum D_{	ext{bonds formed}}$

Question 11

Which of the following salts is insoluble in water according to the solubility rules provided?

Accepted Answer

$\mathrm{AgCl}$

Question 12

What is the final temperature of a 30.0 g gold nugget (specific heat $0.128$ J/g·°C) initially at 200.0°C that loses 425 J of heat to a snowbank?

Accepted Answer

$88.6$ °C

Question 13

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

Accepted Answer

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

Question 14

Which of the following is the correct balanced molecular equation for the reaction between $\mathrm{K_3PO_4(aq)}$ and $\mathrm{AgNO_3(aq)}$?

Accepted Answer

$\mathrm{K_3PO_4(aq) + 3AgNO_3(aq) \rightarrow Ag_3PO_4(s) + 3KNO_3(aq)}$

Question 15

Which of the following is the correct formula for calculating the formal charge on an atom in a Lewis structure?

Accepted Answer

$	ext{Formal charge} = 	ext{valence electrons} - (	ext{lone pairs} + \frac{1}{2} 	imes 	ext{bonding electrons})$

Question 16

Which of the following gases will have the highest root-mean-square speed at 298 K?

Accepted Answer

$\mathrm{H_2}$

Question 17

Which of the following is the correct expression for the standard enthalpy change of a reaction using enthalpies of formation?

Accepted Answer

$\Delta H^\circ_{rxn} = \sum \Delta H^\circ_f(	ext{products}) - \sum \Delta H^\circ_f(	ext{reactants})$

Question 18

Which of the following is the correct balanced redox equation for the reaction between $\mathrm{H_2O_2(aq)}$ and $\mathrm{Cl_2(g)}$ in acidic solution?

Accepted Answer

$\mathrm{H_2O_2(aq) + Cl_2(g) \rightarrow 2HCl(aq) + O_2(g)}$

General Chemistry I: Comprehensive Study Notes and Reference Tables

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