GENERAL CHEMISTRY
Unit 2: MOLE/MASS/ATOMS LAB
*Learning Target Met: Relate the mass of an atom to the number of moles.
Name:______________________
Date:______________Hour:_____
Background:
Counting atoms is difficult; there are so many atoms in anything that we cannot count them individually. A mole
is a way to measure a large quantity of something. We use Avogadro’s number (6.022 x 1023) to represent the number
of atoms in 1 mole of anything. 1 mole = 6.022 x 1023 atoms, particles, molecules of anything. This means 1 mole
Carbon = 6.022 x 1023 atoms Carbon; 1 mole gold = 6.022 x 1023 atoms gold, 1 mole water = 6.022 x 1023 atoms water.
We can also use the molar mass to help us in determining amounts of things. The molar mass represents the
number of grams in 1 mole of anything. The molar mass can be found by using the periodic table, and is the same
mathematical value as the average atomic mass. 1 mole carbon = 12.01 g carbon; 1 mole gold = 196.97 g gold; 1 mole
water (H2O) = 18.02 g water.
In this activity, you will be finding the masses of various substances, and then determining how many atoms or
moles of that substance you have. You will then have a mystery item that you need to determine the identity of.
Instructions:
1. Obtain a sample of a substance (element or compound). Record that sample number in data table #1 below.
2. Determine the mass of that substance with its container and record it in data table #1 below.
3. Determine the mass of the substance by itself by subtracting out the mass of the container and record it in data
table #1 below.
4. Record the molar mass of the substance.
5. Repeat for all substances.
6. Obtain a mystery ELEMENT from your teacher. Record the letter of your substance in the “Mystery” data table.
7. Find the mass of your mystery substance with the container and record it. Then, determine the mass of the
mystery substance itself.
8. There is one mole of the element in your mystery sample. Determine the identity of your mystery element and
record it. The possible mystery elements are any solid element on the Periodic Table.
9. Repeat steps 6-8, but with a mystery COMPOUND instead. There will still only be one mole of the compound.
The possible mystery compounds are: NaCl, FeS, CaCO3, NaHCO3, Na2CO3, MgSO4, C12H22O11
10. Repeat steps 6-9 with one more element and one more compound.
11. Answer the questions regarding each substance.
Data Table #1
ELEMENT OR
COMPOUND
Iron
Aluminum
Copper
Tin
Magnesium
H2O (water)
H2O2
(hydrogen peroxide)
SAMPLE
NUMBER
MASS OF SAMPLE
WITH CONTAINER
MASS OF
CONTAINER
MASS OF
SAMPLE
MOLAR
MASS OF
SUBSTANCE
GENERAL CHEMISTRY
Unit 2: MOLE/MASS/ATOMS LAB
Name:______________________
Date:______________Hour:_____
“Mystery Substance” Data Table
LETTER OF
SUBSTANCE
MASS OF
SAMPLE WITH
CONTAINER
MASS OF
CONTAINER
Mystery
Element #1
Mystery
Element #2
Mystery
Compound #1
Mystery
Compound #2
Post-Lab Questions: Show work for all questions below. No work = No credit!
1. Iron:
a. In the sample of iron, how many moles are there?
b. How many atoms of iron are there in the sample?
2. Aluminum
a. In the sample of aluminum, how many moles are there?
b. How many atoms of aluminum are there in the sample?
3. Copper
a. In the sample of copper, how many moles are there?
b. How many atoms of copper are there in the sample?
4. Tin
a. In the sample of tin, how many moles are there?
MASS OF
SAMPLE
IDENTITY OF
SAMPLE
GENERAL CHEMISTRY
Unit 2: MOLE/MASS/ATOMS LAB
b. How many atoms of tin are there in the sample?
5. Magnesium
a. In the sample of magnesium, how many moles are there?
b. How many atoms of magnesium are there in the sample?
6. Water
a. In the sample of water, how many moles are there?
b. How many atoms of water are there in the sample?
7. Hydrogen Peroxide
a. In the sample of hydrogen peroxide, how many moles are there?
b. How many atoms of hydrogen peroxide are there in the sample?
Extension/Analysis Questions:
8. How many aluminum cans are there in 1 mole of aluminum? Show work!
9. How many atoms are there in 1 iron nail? Show work!
10. How many grams are there in 2.59 x 1028 atoms of carbon?
Name:______________________
Date:______________Hour:_____