Q: A burst of light with a total energy of $485 \text{ kJ}$ is composed of $1.59 \text{ moles}$ of photons. What is the energy per photon?

$5.08 \times 10^{-19} \text{ J}$

Q: Which of the following is the smallest mass?

$7.5 \times 10^{-4} \text{ kg}$

Question 1

Which of the following measurements has the greatest number of significant figures?

Accepted Answer

$7.81 	ext{ g/cm}^3$

Question 2

A graduated cylinder contains water at the 4.3 mL mark. After adding a metal object, the water rises to 6.2 mL. If the mass of the object is 8.5 g, what is its density?

Accepted Answer

$4.47 	ext{ g/mL}$

Question 3

Which of the following substances is best classified as a homogeneous mixture?

Accepted Answer

Substance B

Question 4

An ion has 26 protons, 29 neutrons, and 23 electrons. What is the correct symbol for this ion?

Accepted Answer

$	ext{Fe}^{3+}$

Question 5

A sample of titanium contains $5.03 	imes 10^{24}$ atoms. What is the mass of this sample in grams? (Molar mass of Ti = $47.88 	ext{ g/mol}$)

Accepted Answer

$400 	ext{ g}$

Question 6

Which of the following changes to a sample of rontium (Ro) will result in a different element?

Accepted Answer

Add 2 protons

Question 7

A naturally occurring element has two isotopes: one with a mass of $64.23 	ext{ amu}$ and abundance of $23\%$, and another with a mass of $65.32 	ext{ amu}$ and abundance of $77\%$. What is the average atomic mass?

Accepted Answer

$65.07 	ext{ amu}$

Question 8

Which of the following best describes the difference between an element and a compound?

Accepted Answer

An element is made of only one type of atom, while a compound is made of two or more types of atoms chemically bonded.

Question 9

A burst of light with a total energy of $485 	ext{ kJ}$ is composed of $1.59 	ext{ moles}$ of photons. What is the energy per photon?

Accepted Answer

$5.08 	imes 10^{-19} 	ext{ J}$

Question 10

If the speed of light is $2.998 	imes 10^8 	ext{ m/s}$ and the wavelength of a photon is $3.11 	imes 10^{-7} 	ext{ m}$, what is the frequency of the photon in MHz?

Accepted Answer

$9.65 	imes 10^8 	ext{ MHz}$

Question 11

Which of the following statements about the photoelectric effect is correct?

Accepted Answer

Electrons are ejected only if the frequency of the light is above the threshold frequency for the metal.

Question 12

Which of the following orbitals in the same shell are degenerate?

Accepted Answer

All $p$-orbitals ($p_x$, $p_y$, $p_z$) have the same energy.

Question 13

A student measures the mass of a sample as $21.87 	ext{ g}$ and the volume as $22.87 	ext{ mL}$. What is the density of the sample, reported to the correct number of significant figures?

Accepted Answer

$0.956 	ext{ g/mL}$

Question 14

If gasoline costs $2.64$ per gallon and your car averages $19.1$ miles per gallon, how many miles can you travel in your car with $40.00$?

Accepted Answer

$289 	ext{ miles}$

Question 15

Which of the following is the smallest mass?

Accepted Answer

$7.5 	imes 10^{-4} 	ext{ kg}$

Question 16

Which student’s density measurement is more accurate if the true value is $7.87 	ext{ g/cm}^3$? Student 1: $7.81 	ext{ g/cm}^3$, Student 2: $7.80 	ext{ g/cm}^3$, Student 3: $7.88 	ext{ g/cm}^3$.

Accepted Answer

Student 3

Question 17

Which student’s density measurement is more precise? Student 1: $7.81 	ext{ g/cm}^3$, Student 2: $7.80 	ext{ g/cm}^3$, Student 3: $7.88 	ext{ g/cm}^3$.

Accepted Answer

Student 1

Question 18

Which of the following is a physical change?

Accepted Answer

Boiling water

Question 19

Which of the following is a chemical property?

Accepted Answer

Ability to react with oxygen

General Chemistry Practice Exam 1: Key Concepts and Explanations

Study Guide - Practice Questions

Study Guide - Flashcards