**Purpose: **The purpose of this activity is to determine the number of the formula units of CaCO_{3} (chalk) that are deposited onto a chalk board.

**Procedure:**

**
**

- Carefully record the mass of a piece of chalk.
- Write your name of the chalkboard.
- Reweigh the chalk.

Show a word formula and sample calculation:

- Calculation the mass of chalk deposited onto the board.
- Convert grams of chalk CaCO
_{3}, to formula units.

Compile your

data with that of 9 other classmates. Input into List 1 (L1) of the graphing calculator. Go to stat. Arrow over to calc. Select one variable. Select enter. Find the following:

- The mean () with the standard deviation (S
_{x})
- The range with minimums and maximums
- The median

**Discussion:**

**
**

- What is chalk made of?
- How does it form?
- Why is there so much limestone in Florida?
- Why can you pick up a piece of white limestone off the ground and write your name with it on a sidewalk?
- How many formula units of CaCO
_{3} are in one mole of CaCO_{3}?
- How much does one mole of CaCO
_{3} weigh?
- How many times would you have to write your name to use up 0.50 grams of chalk?