Lesson Activity Print
How Much Is a Mole?
This activity will help you meet these educational goals:
You will apply ratios to solve a complex measurement problem involving derived or compound units.
You will use algebra and mathematical functions to represent and solve scientific problems.
Directions
Read the instructions for this self-checked activity. Submit your response to each question, and check your answers. At the end of the activity, write a brief evaluation of your work.
Activity
This activity will help you get a sense of how big a mole is by doing a series of calculations and comparisons. Consult the math review if you need help with scientific notation or exponents. Consult the rules of significant figures if you need help with significant figures.
Part A
Question 1
Question

Earth has approximately 600,000,000 meters of coastline. If we assume this entire length of coastline has sandy beaches 60 meters wide and 20 meters deep, how many cubic meters of sand are on the beaches?
Express your answer to the correct number of significant figures.
There are × 10 cubic meters of sand on the beaches.
Correct!
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Explanation:
The amount of sand on the beaches can be found using this formula:
volume (m3) = length (m) × width (m) × depth (m)
(6 × 108 m) × 60 m × 20 m = 7 × 1011 m3
Therefore, there would be a total of 7 × 1011 cubic meters of sand on the beaches.
Question 2

Question

A single grain of sand occupies a volume of about 0.004 cubic millimeters. Based on your previous answer, how many grains of sand are on Earth’s beaches?
There are 109 cubic millimeters in each cubic meter. Express your answer to the correct number of significant figures.
There are × 10 grains of sand on the beaches.
Correct!
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Explanation:
Calculate the number of grains in two steps.
First, calculate the volume of one grain of sand in cubic meters:
0.0044 mm3 ×

=

.
Then, calculate the number of grains of sand on the beaches:
7 × 1011 m3 ×

= 2 × 1023 grains.
Question 3

Question

Compare the value you calculated for the number of sand grains on Earth’s beaches to the number of particles in a mole. What can you conclude about the size of a mole?
The number of particles in a mole is about the number of grains of sand on Earth’s beaches.
Correct!
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Explanation:
There are 6.022 × 1023 particles in a mole and about 2 × 1023 grains of sand on Earth’s beaches. The number of particles in a mole is about three times the number of sand grains.
Part B
Question 1
Question

Determine the molar mass of water (H2O) using the periodic table. Express your answer to the correct number of significant figures.
The molar mass of water is grams/mole.
Correct!
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Explanation:
The molar mass of water (H2O) is calculated by adding the molar mass of the individual elements that make up the compound:
(2 × molar mass of hydrogen) + (1 × molar mass of oxygen)
(2 × 1.008 g/mol) + 15.999 g/mol = 18.015 g/mol
Question 2

Question

The density of water is 1.00 gram/milliliter. What is the volume in milliliters of 1.00 mole of water? Express your answer to the correct number of significant figures.
The volume of 1.00 mole of water is milliliters.
Correct!
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Explanation:
Calculate the volume of 1 mole of water:
volume (mL) = mass (g) × density (g/mL)
18.015 g × 1.00 g/mL = 18.0 mL
Part C

Question

Based on what you’ve determined regarding one mole of sand and one mole of water, which statements must be correct?
Select all the correct answers.
The mole is appropriate only for counting things that are very small.
The number of particles in a mole depends on the size of the particles.
One mole is a very large number of something.
A molecule of water is much smaller than a grain of sand.
There are more grains of sand on Earth than there are water molecules.

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Self-Evaluation
How did you do? Rate your work on a scale of 1 to 5, with 5 as the highest score. Then write a brief evaluation of your work below. Note what you learned and what challenged you.

Font Sizes

Given:
N2 + 3H2 → 2NH3
In the chemical reaction, how many grams of nitrogen are needed to completely react with 24.3 grams of hydrogen? Use the periodic table to get the weights of the elements.
Drag each number to the correct location to complete the analysis.