1.
MOLE LAB 1: A MOLE OF BEANS
Chemistry is strange and mysterious. We know, for example, that water is made of two
hydrogens and one oxygen. We know that two hydrogens and one oxygen will make
one water, and we can write that relationship like this:
2H+1O 1 H2O
You would think, then, that we could make some simple inferences about chemistry, like
2 grams of H + 1 gram of O 1 gram of H2O
or possibly, that
2 grams of H + 1 gram of O 3 grams of H2O
But in fact, that doesn t happen. Instead, what we get is:
2.0000 grams of H + 1.0000 gram of O 1.1250 grams of H2O + 1.9375 grams of H
To explain this bizarre occurrence, we need the idea of THE MOLE.
THE MOLE is simply a way to count atoms and molecules not by their mass, but
instead by their number.
This is not such a weird idea in real life. Usually, we count things by their number
anyway — you might go the grocery store and ask for a dozen eggs rather than 850
grams of eggs, or eight oranges rather than 500 grams of oranges.
The problem with atoms and molecules is that they are so small that we have to weigh
them out rather than count them. You can t count molecules of water — not without
millions of dollars of sensitive equipment, anyway — but you can weigh water, so we
invented THE MOLE as a way of going from a mass to a number by using math instead
of using equipment.
To do this in a way that we can understand easily, we need something that we can
weigh out easily, but that is much harder to count. So, we are going to use … BEANS!
2.
PROCEDURE
Each group will receive ONE MOLE of one type of beans from the periodic table of
beans. These beans have been painstakingly divided into MOLES of ONE HUNDRED,
so do not open these bags under penalty of death or 0 points on the lab.
Scattered around the room are also containers of beans which contain an unknown
number of beans. These have been helpfully labeled as UNKNOWN.
(This is different from a real mole, which is approximately 6 x 1023, or six bazillion)
Please follow this procedure:
1. Weigh out your mole of beans.
2. Subtract the weight of your plastic bag to ﬁnd the mass of just the beans. Record this
data in your data table.
3. Weigh out your unknown amount of beans.
4. Trade beans with other groups and repeat steps 1-3.
5. Continue weighing beans until you have weighed all of the different types of beans.
DATA TABLE
Type of Bean Mass of Mole Mass of Unknown
Black Bean
Red Lentil
Brown Bean
Red Bean
Green Lentil
Brown Lentil
Black Eyed Beans
Northern White Beans
Round Tan Beans
3.
DATA ANALYSIS
You are responsible for ﬁnding the number of moles and number of beans in each
unknown bag of beans. To do this, use these two simple procedures:
(# of moles) = (mass of unknown) ÷ (mass of one mole)
(# of beans) = (# of moles) x (# of beans in one mole)
Remember, there are always ONE HUNDRED beans in ONE MOLE of beans,
regardless of how light, how heavy, how big or how small the beans are … just as there
are always 6 x 1023 or six bazillion atoms or molecules in a mole of any chemical.
Show your work for each type of bean on a separate sheet of paper.
1. Black Beans (example)
4.
EXTRA (MANDATORY) QUESTIONS FOR EXTRA (MANDATORY) FUN!!!
You must show your math work for credit.
1. How many moles of beans is 92,078 beans?
2. How many beans would be in 3.14 moles of beans?
3a. Suppose you had a bean that weighed 7.60 grams for a mole. How many moles
would 8.58 grams of this bean be?
3b. How many beans would that make?
4a. How many moles are in a kilogram (1000 grams) of your three favorite types of
beans? (Choose any three beans from this lab).
4b. How many beans?
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