Q: A student mixes 50.0 mL of 0.200 M NaCl with 150.0 mL of 0.100 M NaCl. What is the final concentration of NaCl in the mixture?

$C_f = \frac{(0.200 \times 50.0) + (0.100 \times 150.0)}{50.0 + 150.0} = 0.125\ \mathrm{M}$

Q: A reaction has the following balanced equation: $2KClO_3 \rightarrow 2KCl + 3O_2$. If 12.0 g of $KClO_3$ is decomposed, how many grams of $O_2$ are produced? (Molar masses: $KClO_3 = 122.6\ \mathrm{g/mol}$, $O_2 = 32.0\ \mathrm{g/mol}$)

$12.0\ \mathrm{g}\ KClO_3 \times \frac{1\ \mathrm{mol}}{122.6\ \mathrm{g}} \times \frac{3\ \mathrm{mol}\ O_2}{2\ \mathrm{mol}\ KClO_3} \times 32.0\ \mathrm{g/mol} = 4.70\ \mathrm{g}\ O_2$

Q: A sample of gas occupies 2.50 L at 1.00 atm and 300 K. What will be its volume at 2.00 atm and 300 K?

$V_2 = V_1 \times \frac{P_1}{P_2} = 2.50\ \mathrm{L} \times \frac{1.00}{2.00} = 1.25\ \mathrm{L}$

Question 1

Which of the following best describes the difference between an atom and an ion?

Accepted Answer

An atom is electrically neutral, while an ion has a net positive or negative charge due to loss or gain of electrons.

Question 2

A student mixes 50.0 mL of 0.200 M NaCl with 150.0 mL of 0.100 M NaCl. What is the final concentration of NaCl in the mixture?

Accepted Answer

$C_f = \frac{(0.200 	imes 50.0) + (0.100 	imes 150.0)}{50.0 + 150.0} = 0.125\ \mathrm{M}$

Question 3

Which of the following is the correct electron configuration for a neutral atom of sulfur (S, atomic number 16)?

Accepted Answer

$1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^4$

Question 4

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is the empirical formula of the compound?

Accepted Answer

$CH_2O$

Question 5

Which of the following statements about ionic and covalent bonds is correct?

Accepted Answer

Ionic bonds form between metals and nonmetals, while covalent bonds form between nonmetals.

Question 6

A reaction has the following balanced equation: $2KClO_3 \rightarrow 2KCl + 3O_2$. If 12.0 g of $KClO_3$ is decomposed, how many grams of $O_2$ are produced? (Molar masses: $KClO_3 = 122.6\ \mathrm{g/mol}$, $O_2 = 32.0\ \mathrm{g/mol}$)

Accepted Answer

$12.0\ \mathrm{g}\ KClO_3 	imes \frac{1\ \mathrm{mol}}{122.6\ \mathrm{g}} 	imes \frac{3\ \mathrm{mol}\ O_2}{2\ \mathrm{mol}\ KClO_3} 	imes 32.0\ \mathrm{g/mol} = 4.70\ \mathrm{g}\ O_2$

Question 7

Which of the following best explains why water is a polar molecule?

Accepted Answer

Water has a bent molecular geometry and a significant difference in electronegativity between oxygen and hydrogen.

Question 8

A sample of gas occupies 2.50 L at 1.00 atm and 300 K. What will be its volume at 2.00 atm and 300 K?

Accepted Answer

$V_2 = V_1 	imes \frac{P_1}{P_2} = 2.50\ \mathrm{L} 	imes \frac{1.00}{2.00} = 1.25\ \mathrm{L}$

Question 9

Which of the following is a correct statement about limiting reactants in chemical reactions?

Accepted Answer

The limiting reactant is the reactant that is completely consumed first, thus determining the amount of product formed.

Question 10

Which of the following best describes the process of dissolution when table salt ($NaCl$) is added to water?

Accepted Answer

The $Na^+$ and $Cl^-$ ions are surrounded by water molecules due to ion-dipole interactions.

Question 11

A solution is prepared by dissolving 10.0 g of glucose ($C_6H_{12}O_6$) in enough water to make 250 mL of solution. What is the molarity of the solution? (Molar mass of glucose = $180.2\ \mathrm{g/mol}$)

Accepted Answer

$M = \frac{10.0\ \mathrm{g}}{180.2\ \mathrm{g/mol}} \div 0.250\ \mathrm{L} = 0.222\ \mathrm{M}$

Question 12

Which of the following is the correct net ionic equation for the reaction between $AgNO_3$ and $NaCl$ in aqueous solution?

Accepted Answer

$Ag^+ (aq) + Cl^- (aq) \rightarrow AgCl (s)$

Question 13

Which of the following gases will effuse the fastest under identical conditions?

Accepted Answer

$H_2$

Question 14

Which of the following is the correct formula for calculating percent yield in a chemical reaction?

Accepted Answer

$	ext{Percent Yield} = \frac{	ext{Actual Yield}}{	ext{Theoretical Yield}} 	imes 100\%$

Question 15

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

Accepted Answer

A catalyst provides an alternative pathway with lower activation energy, increasing the reaction rate.

Question 16

A sample of $CaCO_3$ (calcium carbonate) is heated and decomposes according to the equation: $CaCO_3 (s) \rightarrow CaO (s) + CO_2 (g)$. If 50.0 g of $CaCO_3$ is heated, how many liters of $CO_2$ gas are produced at STP? (Molar mass $CaCO_3 = 100.1\ \mathrm{g/mol}$, 1 mol gas at STP = 22.4 L)

Accepted Answer

$50.0\ \mathrm{g}\ CaCO_3 	imes \frac{1\ \mathrm{mol}}{100.1\ \mathrm{g}} 	imes \frac{1\ \mathrm{mol}\ CO_2}{1\ \mathrm{mol}\ CaCO_3} 	imes 22.4\ \mathrm{L} = 11.2\ \mathrm{L}$

Question 17

Which of the following is the correct Lewis structure for $CO_2$?

Accepted Answer

O=C=O, with each oxygen having two lone pairs

Question 18

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

Noble gases have a complete octet in their valence shell, making them stable.

General Chemistry I Syllabus and Course Structure Study Guide

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