1. Counting by Measuring Mass Lab Ms. Mai Lawndale High School You will be working in groups of 4 I only need 1 paper turned in by the end of the period

2. Purpose To measure the mass of three samples of compounds (chalk, salt, and water) Then, use the data to calculate the number of atoms in each sample

3. Materials 3 plastic containers Chalk Salt Water Electronic Balance

4. Procedures 1. Measure the mass of one teaspoon of each chemical in the plastic container 2. Record the mass in your data table 3. When you have measured the mass of your sample, pour the salt and chalk back into the appropriate containers. You can just pour the water down the sink.

5. Data Table H 2 O (l)NaCl (s)CaCO 3 (s) Mass (g) Molar Mass (g/mol) Moles of each Compound Moles of each Element Atoms of each Element