Question 1

Which of the following molecules has a trigonal planar geometry according to VSEPR theory?

Accepted Answer

$\mathrm{BF_3}$

Question 2

Which of the following best describes the hybridization of the central atom in $\mathrm{CH_4}$?

Accepted Answer

$sp^3$

Question 3

A sample of $\mathrm{CaCO_3}$ (molar mass = 100.1 g/mol) is decomposed by heating. If 50.0 g of $\mathrm{CaCO_3}$ is heated and the reaction goes to completion, what is the theoretical yield of $\mathrm{CO_2}$ (in grams) produced? $\mathrm{CaCO_3 (s) \rightarrow CaO (s) + CO_2 (g)}$

Accepted Answer

22.0 g

Question 4

Which of the following statements about hydrogen bonding is correct?

Accepted Answer

Hydrogen bonding occurs when hydrogen is bonded to highly electronegative atoms like N, O, or F.

Question 5

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of $\mathrm{Na_2SO_4}$ and $\mathrm{BaCl_2}$?

Accepted Answer

$\mathrm{Ba^{2+} (aq) + SO_4^{2-} (aq) \rightarrow BaSO_4 (s)}$

Question 6

Which of the following best explains why $\mathrm{H_2O}$ has a higher boiling point than $\mathrm{H_2S}$?

Accepted Answer

$\mathrm{H_2O}$ forms hydrogen bonds, while $\mathrm{H_2S}$ does not.

Question 7

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

Accepted Answer

0.342 M

Question 8

Which of the following is an example of a redox reaction?

Accepted Answer

$\mathrm{2H_2 (g) + O_2 (g) \rightarrow 2H_2O (l)}$

Question 9

Which of the following best describes the difference between an empirical formula and a molecular formula?

Accepted Answer

The molecular formula is always a multiple of the empirical formula.

Question 10

Which of the following is the correct electron configuration for a neutral atom of phosphorus ($Z=15$)?

Accepted Answer

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

Question 11

Which of the following statements about limiting reactants is correct?

Accepted Answer

The limiting reactant determines the maximum amount of product formed.

Question 12

Which of the following best describes why ionic compounds tend to have high melting points?

Accepted Answer

They have strong electrostatic attractions between ions.

Question 13

Which of the following is the correct oxidation state of sulfur in $\mathrm{H_2SO_4}$?

Accepted Answer

+6

Question 14

Which of the following best explains why $\mathrm{CCl_4}$ is nonpolar even though it contains polar bonds?

Accepted Answer

The molecule is tetrahedral, and the bond dipoles cancel due to symmetry.

Question 15

A 0.500 L sample of gas at 1.00 atm and 273 K contains how many moles of gas? (Use $R = 0.0821\ \mathrm{L\ atm\ mol^{-1}\ K^{-1}}$)

Accepted Answer

0.0225 mol

Question 16

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 17

Which of the following best describes the role of a catalyst in a chemical reaction?

Accepted Answer

It lowers the activation energy, increasing the reaction rate.

Question 18

Which of the following is a correct statement about the octet rule?

Accepted Answer

Elements in period 3 and beyond can have expanded octets.

Question 19

Which of the following is the correct formula for calculating percent yield?

Accepted Answer

$\displaystyle \frac{	ext{actual yield}}{	ext{theoretical yield}} 	imes 100\%$

Question 20

Which of the following best describes why ice floats on water?

Accepted Answer

Hydrogen bonding causes ice to have an open hexagonal structure, making it less dense than liquid water.

General Chemistry 1A Final Exam Study Guide: Key Concepts and Topics

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