Question 1

Which of the following best describes the quantum mechanical model of the atom?

Accepted Answer

Electrons exist in defined energy levels but their exact position cannot be determined; instead, their location is described by a probability cloud.

Question 2

Which trend is observed as you move from left to right across a period in the Periodic Table?

Accepted Answer

Atomic radius decreases and ionization energy increases.

Question 3

Which equation correctly relates the energy change ($$\Delta H) in a $$chemical reaction to the enthalpy of products and reactants?

Accepted Answer

$$\Delta H = H_{products} - H_{reactants}$$

Question 4

A student mixes aqueous solutions of silver nitrate and sodium chloride. What type of reaction occurs and what is the precipitate formed?

Accepted Answer

Precipitation reaction; precipitate is AgCl

Question 5

Which statement about covalent bonding according to Lewis theory is correct?

Accepted Answer

Covalent bonds are formed by the sharing of electron pairs between atoms.

Question 6

Which of the following is the correct balanced equation for the combustion of methane ($$CH_4) in $$oxygen?

Accepted Answer

$$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$

Question 7

Which of the following best explains why water ($$H_2O) $$has a higher boiling point than methane ($$CH_4$$)?

Accepted Answer

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

Question 8

Which equation represents the relationship between pressure, volume, and temperature for an ideal gas?

Accepted Answer

$$PV = nRT$$

Question 9

A solution is prepared by dissolving 0.5 mol of NaCl in enough water to make 1.0 L of solution. What is the molarity of the solution?

Accepted Answer

0.5 M

Question 10

Which of the following is a correct statement about Brønsted-Lowry acids and bases?

Accepted Answer

A Brønsted-Lowry acid is a substance that donates a proton.

Question 11

Which of the following best describes the process of oxidation in a redox reaction?

Accepted Answer

Oxidation is the loss of electrons by an atom.

Question 12

Which of the following is the correct formula for calculating pH from the concentration of hydronium ions ($$[H_3O^+]$$)?

Accepted Answer

$$pH = -\log [H_3O^+]$$

Question 13

Which of the following statements about metallic bonding is correct?

Accepted Answer

Metallic bonding involves a 'sea' of delocalized electrons surrounding positive metal ions.

Question 14

A sample of gas occupies 2.0 L at 1.0 atm. If the pressure is increased to 2.0 atm at constant temperature, what will be the new volume?

Accepted Answer

1.0 L

Question 15

Which of the following is the correct electron configuration for a neutral oxygen atom?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^4$$

Question 16

Which of the following is a correct statement about chemical equilibrium?

Accepted Answer

At equilibrium, the rates of the forward and reverse reactions are equal.

Question 17

Which of the following is the correct formula for calculating the equilibrium constant ($$K_{eq}) $$for the reaction $$aA + bB \rightleftharpoons cC + dD$$?

Accepted Answer

$$K_{eq} = \frac{[C]^c [D]^d}{[A]^a [B]^b}$$

Question 18

Which of the following is the correct IUPAC name for the compound $$CH_3CH_2OH$$?

Accepted Answer

Ethanol

Question 19

A reaction has an activation energy of 50 kJ/mol. If a catalyst is added, which of the following best describes the effect?

Accepted Answer

The activation energy decreases and the reaction rate increases.

Question 20

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

Accepted Answer

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

General Chemistry I (CHEM135) Syllabus and Course Overview

Guida di studio - Domande di pratica

Study guide - Flashcard