With a partner and a piece of paper…
1. Each of you get a cup. Dry it out. Record its mass.
2. Obtain 50 beans of one type in the cup and record mass.
Return beans to correct container.
3. Repeat with each of the 5 bean types.

The Bean Lab (put this in your notebook)
• Objectives
– To determine the relative atomic masses by creating relative bean masses
– To establish a standard counting quantity for beans that provides an analogy to the mole

Using the data table to report results ,
• Determine the mass of 50 of each type of bean in a cup
• Determine the mass of 50 beans alone
• Divide the mass of 50 beans by the one that gave the smallest result to determine “relative mass”. Your smallest bean mass will become
ONE when you divide it, also, by itself and everything else will be compared to it.
• Place enough beans on the balance to equal the RELATIVE MASS of each type of bean.
This is the “number of beans in a pot”.

Results
• Data
Type of
Bean
Symbol Mass of cup and
50 beans
Lentil Le
Mass of
50 beans alone
Relative
Mass
Number of beans in 1 Pot
Lima L
Navy N
Kidney K
Soy S

Substance hydrogen carbon oxygen sulfur calcium chlorine copper
Mole and Mass Relationships
Particles in 1 mole Mass of 1 mole
6.022 x 10 23 1.008 g
6.022 x 10 23 12.01 g
6.022 x 10 23
6.022 x 10 23
6.022 x 10 23
6.022 x 10 23
6.022 x 10 23
16.00 g
32.06 g
40.08 g
35.45 g
63.55 g

Calculations and Questions
• Calculation: Relative mass; Average # of beans in a pot +/- uncertainty
Questions:
1.
A “pot” of beans is the number needed to make up the relative mass.
Compare the # in a pot for each bean.
Why isn’t the number the same for all?
2. What was the average # per pot including uncertainty?

Questions continued
3. Calculate: (sample on next slide) a. # pots in 250 g navy beans b. # beans in 250 grams kidney beans c. # pots in 250 lima beans d. # beans in 3.17 pots of any bean e. # grams in 3.17 pots lentils
4. In which of the above conversions does the type of bean not matter (same result)? Explain.

Using known ratios to solve unknown relationships:
• Here are the facts we know from our experiment:
• Use known ratios set equal to the unknown ratio (this is a proportion)
– 3a.

Questions continued
5. Why did you have to round answers to the nearest bean? How is this parallel to atoms?
Discussion: In a well-developed paragraph, write a standard discussion. Include how this lab activity provides an analogy to the mole and beans are analogous to chemical particles.