Chemical Dominoes Activity 3

East High Chemistry Group

Name ______Period ______Chapter 4 – Chemical Dominoes Activity 3 Outline: Counting by Weighing page 274-286

What Do You See?

What Do You Think? How could you determine the number of jelly beans in the jar shown above?

Investigate

Part A: Counting By Weighing

1. Get a bag of beans, a single bean, and a balance.

2. Figure out how many beans are in the bag. Do not open the bag or count the beans individually.

3. Write down any data that you get and any calculations you do in the space below. 4. Explain in writing how to figure out the number of beans in the bag.

5. If you have a bunch of beans with a mass of 143 g, how many beans do you have? Show your work or explain how you got your answer. Part B: Counting Atoms By Weight

1. We count atoms by weighing them, just like you did with the beans in Part A.

What unit do we use to count atoms?

How many atoms are in 1 mole?

2. The mass of 1 mole of any element is equal to the element’s atomic mass on the periodic table. Use a periodic table to figure out the mass of 1 mole of each element listed below.

Element Mass of 1 mole in grams C, carbon O, oxygen Pb, lead Ca, calcium Fe, iron Zn, zinc K, potassium

3. Sometimes you will also have to know the mass of 1 mole of a compound, not just an element.

How could you figure out the mass of 1 mole of water, H2O?

4. Calculate the mass of 1 mole of each of these compounds:

NaCl CuSO4

Fe2O3

CoSO4

NaHCO3 CaCl2

NiSO4

C12H22O11

Part C – More Practice with Molar Mass

Calculate the molar mass of the following compounds.

CO2

MgSO3

K3PO4 KMnO4

ZnCr2O7

SF6

(NH4)2CO3

Part D: The Mole Lab Procedure:

1. When your teacher tells you to begin, go to one of the lab stations. It does not matter where you begin as long as you go to all of the stations.

2. Determine the mass of the element or compound with its container. Record this value in your data table.

3. To save you time, the mass of the container is recorded on the card at the station. Record the mass of the container in your data table.

4. Calculate the mass of the unknown sample.

5. Find the mass of one mole of the unknown. For some of the unknowns you have exactly 6.02 x 1023 atoms, or one mole, so this calculation is already done. Record this information in your data table.

6. Once you have calculated the mass of one mole, refer to your periodic table and the calculations you did in Part B to find the identity of the unknown. Record the identity of the unknown in your data table.

7. Write a brief physical description of the element or compound. Chemists often identify elements from their physical properties.

8. Rezero the balance before leaving the lab station.

Good luck in learning the identities of the elements. May the mole be with you! Station 1. Element Mass of beaker and unknown Mass of empty beaker Mass of unknown Number of moles of unknown Mass of 1 mole of the unknown Identity of unknown