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

Mass of 50 beans alone

Relative Mass

Number of beans in 1 Pot

Lentil Le

Lima L

Navy N

Kidney K

Soy S

Mole and Mass Relationships

Substance Particles in 1 mole Mass of 1 mole

hydrogen 6.022 x 1023 1.008 g

carbon 6.022 x 1023 12.01 g

oxygen 6.022 x 1023 16.00 g

sulfur 6.022 x 1023 32.06 g

calcium 6.022 x 1023 40.08 g

chlorine 6.022 x 1023 35.45 g

copper 6.022 x 1023 63.55 g

Calculations and Questions• Calculation: Relative mass; Average #

of beans in a pot +/- uncertaintyQuestions: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 beansb. # beans in 250 grams kidney beansc. # pots in 250 lima beansd. # beans in 3.17 pots of any beane. # 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.